root/tools/testing/selftests/net/nettest.c
// SPDX-License-Identifier: GPL-2.0
/* nettest - used for functional tests of networking APIs
 *
 * Copyright (c) 2013-2019 David Ahern <dsahern@gmail.com>. All rights reserved.
 */

#define _GNU_SOURCE
#include <features.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <sched.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <getopt.h>

#include <linux/xfrm.h>
#include <linux/ipsec.h>
#include <linux/pfkeyv2.h>

#ifndef IPV6_UNICAST_IF
#define IPV6_UNICAST_IF         76
#endif
#ifndef IPV6_MULTICAST_IF
#define IPV6_MULTICAST_IF       17
#endif

#define DEFAULT_PORT 12345

#define NS_PREFIX "/run/netns/"

#ifndef MAX
#define MAX(a, b)  ((a) > (b) ? (a) : (b))
#endif
#ifndef MIN
#define MIN(a, b)  ((a) < (b) ? (a) : (b))
#endif

struct sock_args {
        /* local address */
        const char *local_addr_str;
        const char *client_local_addr_str;
        union {
                struct in_addr  in;
                struct in6_addr in6;
        } local_addr;

        /* remote address */
        const char *remote_addr_str;
        union {
                struct in_addr  in;
                struct in6_addr in6;
        } remote_addr;
        int scope_id;  /* remote scope; v6 send only */

        struct in_addr grp;     /* multicast group */

        unsigned int has_local_ip:1,
                     has_remote_ip:1,
                     has_grp:1,
                     has_expected_laddr:1,
                     has_expected_raddr:1,
                     bind_test_only:1,
                     client_dontroute:1,
                     server_dontroute:1;

        unsigned short port;

        int type;      /* DGRAM, STREAM, RAW */
        int protocol;
        int version;   /* AF_INET/AF_INET6 */

        int use_setsockopt;
        int use_freebind;
        int use_cmsg;
        uint8_t dsfield;
        const char *dev;
        const char *server_dev;
        int ifindex;

        const char *clientns;
        const char *serverns;

        const char *password;
        const char *client_pw;
        /* prefix for MD5 password */
        const char *md5_prefix_str;
        union {
                struct sockaddr_in v4;
                struct sockaddr_in6 v6;
        } md5_prefix;
        unsigned int prefix_len;
        /* 0: default, -1: force off, +1: force on */
        int bind_key_ifindex;

        /* expected addresses and device index for connection */
        const char *expected_dev;
        const char *expected_server_dev;
        int expected_ifindex;

        /* local address */
        const char *expected_laddr_str;
        union {
                struct in_addr  in;
                struct in6_addr in6;
        } expected_laddr;

        /* remote address */
        const char *expected_raddr_str;
        union {
                struct in_addr  in;
                struct in6_addr in6;
        } expected_raddr;

        /* ESP in UDP encap test */
        int use_xfrm;

        /* use send() and connect() instead of sendto */
        int datagram_connect;
};

static int server_mode;
static unsigned int prog_timeout = 5;
static unsigned int interactive;
static int iter = 1;
static char *msg = "Hello world!";
static int msglen;
static int quiet;
static int try_broadcast = 1;

static char *timestamp(char *timebuf, int buflen)
{
        time_t now;

        now = time(NULL);
        if (strftime(timebuf, buflen, "%T", localtime(&now)) == 0) {
                memset(timebuf, 0, buflen);
                strncpy(timebuf, "00:00:00", buflen-1);
        }

        return timebuf;
}

static void log_msg(const char *format, ...)
{
        char timebuf[64];
        va_list args;

        if (quiet)
                return;

        fprintf(stdout, "%s %s:",
                timestamp(timebuf, sizeof(timebuf)),
                server_mode ? "server" : "client");
        va_start(args, format);
        vfprintf(stdout, format, args);
        va_end(args);

        fflush(stdout);
}

static void log_error(const char *format, ...)
{
        char timebuf[64];
        va_list args;

        if (quiet)
                return;

        fprintf(stderr, "%s %s:",
                timestamp(timebuf, sizeof(timebuf)),
                server_mode ? "server" : "client");
        va_start(args, format);
        vfprintf(stderr, format, args);
        va_end(args);

        fflush(stderr);
}

static void log_err_errno(const char *fmt, ...)
{
        char timebuf[64];
        va_list args;

        if (quiet)
                return;

        fprintf(stderr, "%s %s: ",
                timestamp(timebuf, sizeof(timebuf)),
                server_mode ? "server" : "client");
        va_start(args, fmt);
        vfprintf(stderr, fmt, args);
        va_end(args);

        fprintf(stderr, ": %d: %s\n", errno, strerror(errno));
        fflush(stderr);
}

static void log_address(const char *desc, struct sockaddr *sa)
{
        char addrstr[64];

        if (quiet)
                return;

        if (sa->sa_family == AF_INET) {
                struct sockaddr_in *s = (struct sockaddr_in *) sa;

                log_msg("%s %s:%d\n",
                        desc,
                        inet_ntop(AF_INET, &s->sin_addr, addrstr,
                                  sizeof(addrstr)),
                        ntohs(s->sin_port));

        } else if (sa->sa_family == AF_INET6) {
                struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) sa;

                log_msg("%s [%s]:%d\n",
                        desc,
                        inet_ntop(AF_INET6, &s6->sin6_addr, addrstr,
                                  sizeof(addrstr)),
                        ntohs(s6->sin6_port));
        }

        fflush(stdout);
}

static int switch_ns(const char *ns)
{
        char path[PATH_MAX];
        int fd, ret;

        if (geteuid())
                log_error("warning: likely need root to set netns %s!\n", ns);

        snprintf(path, sizeof(path), "%s%s", NS_PREFIX, ns);
        fd = open(path, 0);
        if (fd < 0) {
                log_err_errno("Failed to open netns path; can not switch netns");
                return 1;
        }

        ret = setns(fd, CLONE_NEWNET);
        close(fd);

        return ret;
}

static int tcp_md5sig(int sd, void *addr, socklen_t alen, struct sock_args *args)
{
        int keylen = strlen(args->password);
        struct tcp_md5sig md5sig = {};
        int opt = TCP_MD5SIG;
        int rc;

        md5sig.tcpm_keylen = keylen;
        memcpy(md5sig.tcpm_key, args->password, keylen);

        if (args->prefix_len) {
                opt = TCP_MD5SIG_EXT;
                md5sig.tcpm_flags |= TCP_MD5SIG_FLAG_PREFIX;

                md5sig.tcpm_prefixlen = args->prefix_len;
                addr = &args->md5_prefix;
        }
        memcpy(&md5sig.tcpm_addr, addr, alen);

        if ((args->ifindex && args->bind_key_ifindex >= 0) || args->bind_key_ifindex >= 1) {
                opt = TCP_MD5SIG_EXT;
                md5sig.tcpm_flags |= TCP_MD5SIG_FLAG_IFINDEX;

                md5sig.tcpm_ifindex = args->ifindex;
                log_msg("TCP_MD5SIG_FLAG_IFINDEX set tcpm_ifindex=%d\n", md5sig.tcpm_ifindex);
        } else {
                log_msg("TCP_MD5SIG_FLAG_IFINDEX off\n", md5sig.tcpm_ifindex);
        }

        rc = setsockopt(sd, IPPROTO_TCP, opt, &md5sig, sizeof(md5sig));
        if (rc < 0) {
                /* ENOENT is harmless. Returned when a password is cleared */
                if (errno == ENOENT)
                        rc = 0;
                else
                        log_err_errno("setsockopt(TCP_MD5SIG)");
        }

        return rc;
}

static int tcp_md5_remote(int sd, struct sock_args *args)
{
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
        };
        struct sockaddr_in6 sin6 = {
                .sin6_family = AF_INET6,
        };
        void *addr;
        int alen;

        switch (args->version) {
        case AF_INET:
                sin.sin_port = htons(args->port);
                sin.sin_addr = args->md5_prefix.v4.sin_addr;
                addr = &sin;
                alen = sizeof(sin);
                break;
        case AF_INET6:
                sin6.sin6_port = htons(args->port);
                sin6.sin6_addr = args->md5_prefix.v6.sin6_addr;
                addr = &sin6;
                alen = sizeof(sin6);
                break;
        default:
                log_error("unknown address family\n");
                exit(1);
        }

        if (tcp_md5sig(sd, addr, alen, args))
                return -1;

        return 0;
}

static int get_ifidx(const char *ifname)
{
        struct ifreq ifdata;
        int sd, rc;

        if (!ifname || *ifname == '\0')
                return -1;

        memset(&ifdata, 0, sizeof(ifdata));

        strcpy(ifdata.ifr_name, ifname);

        sd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
        if (sd < 0) {
                log_err_errno("socket failed");
                return -1;
        }

        rc = ioctl(sd, SIOCGIFINDEX, (char *)&ifdata);
        close(sd);
        if (rc != 0) {
                log_err_errno("ioctl(SIOCGIFINDEX) failed");
                return -1;
        }

        return ifdata.ifr_ifindex;
}

static int bind_to_device(int sd, const char *name)
{
        int rc;

        rc = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, name, strlen(name)+1);
        if (rc < 0)
                log_err_errno("setsockopt(SO_BINDTODEVICE)");

        return rc;
}

static int get_bind_to_device(int sd, char *name, size_t len)
{
        int rc;
        socklen_t optlen = len;

        name[0] = '\0';
        rc = getsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, name, &optlen);
        if (rc < 0)
                log_err_errno("getsockopt(SO_BINDTODEVICE)");

        return rc;
}

static int check_device(int sd, struct sock_args *args)
{
        int ifindex = 0;
        char name[32];

        if (get_bind_to_device(sd, name, sizeof(name)))
                *name = '\0';
        else
                ifindex = get_ifidx(name);

        log_msg("    bound to device %s/%d\n",
                *name ? name : "<none>", ifindex);

        if (!args->expected_ifindex)
                return 0;

        if (args->expected_ifindex != ifindex) {
                log_error("Device index mismatch: expected %d have %d\n",
                          args->expected_ifindex, ifindex);
                return 1;
        }

        log_msg("Device index matches: expected %d have %d\n",
                args->expected_ifindex, ifindex);

        return 0;
}

static int set_pktinfo_v4(int sd)
{
        int one = 1;
        int rc;

        rc = setsockopt(sd, SOL_IP, IP_PKTINFO, &one, sizeof(one));
        if (rc < 0 && rc != -ENOTSUP)
                log_err_errno("setsockopt(IP_PKTINFO)");

        return rc;
}

static int set_recvpktinfo_v6(int sd)
{
        int one = 1;
        int rc;

        rc = setsockopt(sd, SOL_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one));
        if (rc < 0 && rc != -ENOTSUP)
                log_err_errno("setsockopt(IPV6_RECVPKTINFO)");

        return rc;
}

static int set_recverr_v4(int sd)
{
        int one = 1;
        int rc;

        rc = setsockopt(sd, SOL_IP, IP_RECVERR, &one, sizeof(one));
        if (rc < 0 && rc != -ENOTSUP)
                log_err_errno("setsockopt(IP_RECVERR)");

        return rc;
}

static int set_recverr_v6(int sd)
{
        int one = 1;
        int rc;

        rc = setsockopt(sd, SOL_IPV6, IPV6_RECVERR, &one, sizeof(one));
        if (rc < 0 && rc != -ENOTSUP)
                log_err_errno("setsockopt(IPV6_RECVERR)");

        return rc;
}

static int set_unicast_if(int sd, int ifindex, int version)
{
        int opt = IP_UNICAST_IF;
        int level = SOL_IP;
        int rc;

        ifindex = htonl(ifindex);

        if (version == AF_INET6) {
                opt = IPV6_UNICAST_IF;
                level = SOL_IPV6;
        }
        rc = setsockopt(sd, level, opt, &ifindex, sizeof(ifindex));
        if (rc < 0)
                log_err_errno("setsockopt(IP_UNICAST_IF)");

        return rc;
}

static int set_multicast_if(int sd, int ifindex)
{
        struct ip_mreqn mreq = { .imr_ifindex = ifindex };
        int rc;

        rc = setsockopt(sd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq));
        if (rc < 0)
                log_err_errno("setsockopt(IP_MULTICAST_IF)");

        return rc;
}

static int set_membership(int sd, uint32_t grp, uint32_t addr, int ifindex)
{
        uint32_t if_addr = addr;
        struct ip_mreqn mreq;
        int rc;

        if (addr == htonl(INADDR_ANY) && !ifindex) {
                log_error("Either local address or device needs to be given for multicast membership\n");
                return -1;
        }

        mreq.imr_multiaddr.s_addr = grp;
        mreq.imr_address.s_addr = if_addr;
        mreq.imr_ifindex = ifindex;

        rc = setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
        if (rc < 0) {
                log_err_errno("setsockopt(IP_ADD_MEMBERSHIP)");
                return -1;
        }

        return 0;
}

static int set_freebind(int sd, int version)
{
        unsigned int one = 1;
        int rc = 0;

        switch (version) {
        case AF_INET:
                if (setsockopt(sd, SOL_IP, IP_FREEBIND, &one, sizeof(one))) {
                        log_err_errno("setsockopt(IP_FREEBIND)");
                        rc = -1;
                }
                break;
        case AF_INET6:
                if (setsockopt(sd, SOL_IPV6, IPV6_FREEBIND, &one, sizeof(one))) {
                        log_err_errno("setsockopt(IPV6_FREEBIND)");
                        rc = -1;
                }
                break;
        }

        return rc;
}

static int set_broadcast(int sd)
{
        unsigned int one = 1;
        int rc = 0;

        if (setsockopt(sd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one)) != 0) {
                log_err_errno("setsockopt(SO_BROADCAST)");
                rc = -1;
        }

        return rc;
}

static int set_reuseport(int sd)
{
        unsigned int one = 1;
        int rc = 0;

        if (setsockopt(sd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one)) != 0) {
                log_err_errno("setsockopt(SO_REUSEPORT)");
                rc = -1;
        }

        return rc;
}

static int set_reuseaddr(int sd)
{
        unsigned int one = 1;
        int rc = 0;

        if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) != 0) {
                log_err_errno("setsockopt(SO_REUSEADDR)");
                rc = -1;
        }

        return rc;
}

static int set_dsfield(int sd, int version, int dsfield)
{
        if (!dsfield)
                return 0;

        switch (version) {
        case AF_INET:
                if (setsockopt(sd, SOL_IP, IP_TOS, &dsfield,
                               sizeof(dsfield)) < 0) {
                        log_err_errno("setsockopt(IP_TOS)");
                        return -1;
                }
                break;

        case AF_INET6:
                if (setsockopt(sd, SOL_IPV6, IPV6_TCLASS, &dsfield,
                               sizeof(dsfield)) < 0) {
                        log_err_errno("setsockopt(IPV6_TCLASS)");
                        return -1;
                }
                break;

        default:
                log_error("Invalid address family\n");
                return -1;
        }

        return 0;
}

static int set_dontroute(int sd)
{
        unsigned int one = 1;

        if (setsockopt(sd, SOL_SOCKET, SO_DONTROUTE, &one, sizeof(one)) < 0) {
                log_err_errno("setsockopt(SO_DONTROUTE)");
                return -1;
        }

        return 0;
}

static int str_to_uint(const char *str, int min, int max, unsigned int *value)
{
        int number;
        char *end;

        errno = 0;
        number = (unsigned int) strtoul(str, &end, 0);

        /* entire string should be consumed by conversion
         * and value should be between min and max
         */
        if (((*end == '\0') || (*end == '\n')) && (end != str) &&
            (errno != ERANGE) && (min <= number) && (number <= max)) {
                *value = number;
                return 0;
        }

        return -1;
}

static int resolve_devices(struct sock_args *args)
{
        if (args->dev) {
                args->ifindex = get_ifidx(args->dev);
                if (args->ifindex < 0) {
                        log_error("Invalid device name\n");
                        return 1;
                }
        }

        if (args->expected_dev) {
                unsigned int tmp;

                if (str_to_uint(args->expected_dev, 0, INT_MAX, &tmp) == 0) {
                        args->expected_ifindex = (int)tmp;
                } else {
                        args->expected_ifindex = get_ifidx(args->expected_dev);
                        if (args->expected_ifindex < 0) {
                                fprintf(stderr, "Invalid expected device\n");
                                return 1;
                        }
                }
        }

        return 0;
}

static int expected_addr_match(struct sockaddr *sa, void *expected,
                               const char *desc)
{
        char addrstr[64];
        int rc = 0;

        if (sa->sa_family == AF_INET) {
                struct sockaddr_in *s = (struct sockaddr_in *) sa;
                struct in_addr *exp_in = (struct in_addr *) expected;

                if (s->sin_addr.s_addr != exp_in->s_addr) {
                        log_error("%s address does not match expected %s\n",
                                  desc,
                                  inet_ntop(AF_INET, exp_in,
                                            addrstr, sizeof(addrstr)));
                        rc = 1;
                }
        } else if (sa->sa_family == AF_INET6) {
                struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) sa;
                struct in6_addr *exp_in = (struct in6_addr *) expected;

                if (memcmp(&s6->sin6_addr, exp_in, sizeof(*exp_in))) {
                        log_error("%s address does not match expected %s\n",
                                  desc,
                                  inet_ntop(AF_INET6, exp_in,
                                            addrstr, sizeof(addrstr)));
                        rc = 1;
                }
        } else {
                log_error("%s address does not match expected - unknown family\n",
                          desc);
                rc = 1;
        }

        if (!rc)
                log_msg("%s address matches expected\n", desc);

        return rc;
}

static int show_sockstat(int sd, struct sock_args *args)
{
        struct sockaddr_in6 local_addr, remote_addr;
        socklen_t alen = sizeof(local_addr);
        struct sockaddr *sa;
        const char *desc;
        int rc = 0;

        desc = server_mode ? "server local:" : "client local:";
        sa = (struct sockaddr *) &local_addr;
        if (getsockname(sd, sa, &alen) == 0) {
                log_address(desc, sa);

                if (args->has_expected_laddr) {
                        rc = expected_addr_match(sa, &args->expected_laddr,
                                                 "local");
                }
        } else {
                log_err_errno("getsockname failed");
        }

        sa = (struct sockaddr *) &remote_addr;
        desc = server_mode ? "server peer:" : "client peer:";
        if (getpeername(sd, sa, &alen) == 0) {
                log_address(desc, sa);

                if (args->has_expected_raddr) {
                        rc |= expected_addr_match(sa, &args->expected_raddr,
                                                 "remote");
                }
        } else {
                log_err_errno("getpeername failed");
        }

        return rc;
}

enum addr_type {
        ADDR_TYPE_LOCAL,
        ADDR_TYPE_REMOTE,
        ADDR_TYPE_MCAST,
        ADDR_TYPE_EXPECTED_LOCAL,
        ADDR_TYPE_EXPECTED_REMOTE,
        ADDR_TYPE_MD5_PREFIX,
};

static int convert_addr(struct sock_args *args, const char *_str,
                        enum addr_type atype)
{
        int pfx_len_max = args->version == AF_INET6 ? 128 : 32;
        int family = args->version;
        char *str, *dev, *sep;
        struct in6_addr *in6;
        struct in_addr  *in;
        const char *desc;
        void *addr;
        int rc = 0;

        str = strdup(_str);
        if (!str)
                return -ENOMEM;

        switch (atype) {
        case ADDR_TYPE_LOCAL:
                desc = "local";
                addr = &args->local_addr;
                break;
        case ADDR_TYPE_REMOTE:
                desc = "remote";
                addr = &args->remote_addr;
                break;
        case ADDR_TYPE_MCAST:
                desc = "mcast grp";
                addr = &args->grp;
                break;
        case ADDR_TYPE_EXPECTED_LOCAL:
                desc = "expected local";
                addr = &args->expected_laddr;
                break;
        case ADDR_TYPE_EXPECTED_REMOTE:
                desc = "expected remote";
                addr = &args->expected_raddr;
                break;
        case ADDR_TYPE_MD5_PREFIX:
                desc = "md5 prefix";
                if (family == AF_INET) {
                        args->md5_prefix.v4.sin_family = AF_INET;
                        addr = &args->md5_prefix.v4.sin_addr;
                } else if (family == AF_INET6) {
                        args->md5_prefix.v6.sin6_family = AF_INET6;
                        addr = &args->md5_prefix.v6.sin6_addr;
                } else
                        return 1;

                sep = strchr(str, '/');
                if (sep) {
                        *sep = '\0';
                        sep++;
                        if (str_to_uint(sep, 1, pfx_len_max,
                                        &args->prefix_len) != 0) {
                                fprintf(stderr, "Invalid prefix length\n");
                                return 1;
                        }
                } else {
                        args->prefix_len = 0;
                }
                break;
        default:
                log_error("unknown address type\n");
                exit(1);
        }

        switch (family) {
        case AF_INET:
                in  = (struct in_addr *) addr;
                if (str) {
                        if (inet_pton(AF_INET, str, in) == 0) {
                                log_error("Invalid %s IP address\n", desc);
                                rc = -1;
                                goto out;
                        }
                } else {
                        in->s_addr = htonl(INADDR_ANY);
                }
                break;

        case AF_INET6:
                dev = strchr(str, '%');
                if (dev) {
                        *dev = '\0';
                        dev++;
                }

                in6 = (struct in6_addr *) addr;
                if (str) {
                        if (inet_pton(AF_INET6, str, in6) == 0) {
                                log_error("Invalid %s IPv6 address\n", desc);
                                rc = -1;
                                goto out;
                        }
                } else {
                        *in6 = in6addr_any;
                }
                if (dev) {
                        args->scope_id = get_ifidx(dev);
                        if (args->scope_id < 0) {
                                log_error("Invalid scope on %s IPv6 address\n",
                                          desc);
                                rc = -1;
                                goto out;
                        }
                }
                break;

        default:
                log_error("Invalid address family\n");
        }

out:
        free(str);
        return rc;
}

static int validate_addresses(struct sock_args *args)
{
        if (args->local_addr_str &&
            convert_addr(args, args->local_addr_str, ADDR_TYPE_LOCAL) < 0)
                return 1;

        if (args->remote_addr_str &&
            convert_addr(args, args->remote_addr_str, ADDR_TYPE_REMOTE) < 0)
                return 1;

        if (args->md5_prefix_str &&
            convert_addr(args, args->md5_prefix_str,
                         ADDR_TYPE_MD5_PREFIX) < 0)
                return 1;

        if (args->expected_laddr_str &&
            convert_addr(args, args->expected_laddr_str,
                         ADDR_TYPE_EXPECTED_LOCAL))
                return 1;

        if (args->expected_raddr_str &&
            convert_addr(args, args->expected_raddr_str,
                         ADDR_TYPE_EXPECTED_REMOTE))
                return 1;

        return 0;
}

static int get_index_from_cmsg(struct msghdr *m)
{
        struct cmsghdr *cm;
        int ifindex = 0;
        char buf[64];

        for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(m);
             m->msg_controllen != 0 && cm;
             cm = (struct cmsghdr *)CMSG_NXTHDR(m, cm)) {

                if (cm->cmsg_level == SOL_IP &&
                    cm->cmsg_type == IP_PKTINFO) {
                        struct in_pktinfo *pi;

                        pi = (struct in_pktinfo *)(CMSG_DATA(cm));
                        inet_ntop(AF_INET, &pi->ipi_addr, buf, sizeof(buf));
                        ifindex = pi->ipi_ifindex;
                } else if (cm->cmsg_level == SOL_IPV6 &&
                           cm->cmsg_type == IPV6_PKTINFO) {
                        struct in6_pktinfo *pi6;

                        pi6 = (struct in6_pktinfo *)(CMSG_DATA(cm));
                        inet_ntop(AF_INET6, &pi6->ipi6_addr, buf, sizeof(buf));
                        ifindex = pi6->ipi6_ifindex;
                }
        }

        if (ifindex) {
                log_msg("    pktinfo: ifindex %d dest addr %s\n",
                        ifindex, buf);
        }
        return ifindex;
}

static int send_msg_no_cmsg(int sd, void *addr, socklen_t alen)
{
        int err;

again:
        err = sendto(sd, msg, msglen, 0, addr, alen);
        if (err < 0) {
                if (errno == EACCES && try_broadcast) {
                        try_broadcast = 0;
                        if (!set_broadcast(sd))
                                goto again;
                        errno = EACCES;
                }

                log_err_errno("sendto failed");
                return 1;
        }

        return 0;
}

static int send_msg_cmsg(int sd, void *addr, socklen_t alen,
                         int ifindex, int version)
{
        unsigned char cmsgbuf[64];
        struct iovec iov[2];
        struct cmsghdr *cm;
        struct msghdr m;
        int err;

        iov[0].iov_base = msg;
        iov[0].iov_len = msglen;
        m.msg_iov = iov;
        m.msg_iovlen = 1;
        m.msg_name = (caddr_t)addr;
        m.msg_namelen = alen;

        memset(cmsgbuf, 0, sizeof(cmsgbuf));
        cm = (struct cmsghdr *)cmsgbuf;
        m.msg_control = (caddr_t)cm;

        if (version == AF_INET) {
                struct in_pktinfo *pi;

                cm->cmsg_level = SOL_IP;
                cm->cmsg_type = IP_PKTINFO;
                cm->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
                pi = (struct in_pktinfo *)(CMSG_DATA(cm));
                pi->ipi_ifindex = ifindex;

                m.msg_controllen = cm->cmsg_len;

        } else if (version == AF_INET6) {
                struct in6_pktinfo *pi6;

                cm->cmsg_level = SOL_IPV6;
                cm->cmsg_type = IPV6_PKTINFO;
                cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));

                pi6 = (struct in6_pktinfo *)(CMSG_DATA(cm));
                pi6->ipi6_ifindex = ifindex;

                m.msg_controllen = cm->cmsg_len;
        }

again:
        err = sendmsg(sd, &m, 0);
        if (err < 0) {
                if (errno == EACCES && try_broadcast) {
                        try_broadcast = 0;
                        if (!set_broadcast(sd))
                                goto again;
                        errno = EACCES;
                }

                log_err_errno("sendmsg failed");
                return 1;
        }

        return 0;
}


static int send_msg(int sd, void *addr, socklen_t alen, struct sock_args *args)
{
        if (args->type == SOCK_STREAM) {
                if (write(sd, msg, msglen) < 0) {
                        log_err_errno("write failed sending msg to peer");
                        return 1;
                }
        } else if (args->datagram_connect) {
                if (send(sd, msg, msglen, 0) < 0) {
                        log_err_errno("send failed sending msg to peer");
                        return 1;
                }
        } else if (args->ifindex && args->use_cmsg) {
                if (send_msg_cmsg(sd, addr, alen, args->ifindex, args->version))
                        return 1;
        } else {
                if (send_msg_no_cmsg(sd, addr, alen))
                        return 1;
        }

        log_msg("Sent message:\n");
        log_msg("    %.24s%s\n", msg, msglen > 24 ? " ..." : "");

        return 0;
}

static int socket_read_dgram(int sd, struct sock_args *args)
{
        unsigned char addr[sizeof(struct sockaddr_in6)];
        struct sockaddr *sa = (struct sockaddr *) addr;
        socklen_t alen = sizeof(addr);
        struct iovec iov[2];
        struct msghdr m = {
                .msg_name = (caddr_t)addr,
                .msg_namelen = alen,
                .msg_iov = iov,
                .msg_iovlen = 1,
        };
        unsigned char cmsgbuf[256];
        struct cmsghdr *cm = (struct cmsghdr *)cmsgbuf;
        char buf[16*1024];
        int ifindex;
        int len;

        iov[0].iov_base = (caddr_t)buf;
        iov[0].iov_len = sizeof(buf);

        memset(cmsgbuf, 0, sizeof(cmsgbuf));
        m.msg_control = (caddr_t)cm;
        m.msg_controllen = sizeof(cmsgbuf);

        len = recvmsg(sd, &m, 0);
        if (len == 0) {
                log_msg("peer closed connection.\n");
                return 0;
        } else if (len < 0) {
                log_msg("failed to read message: %d: %s\n",
                        errno, strerror(errno));
                return -1;
        }

        buf[len] = '\0';

        log_address("Message from:", sa);
        log_msg("    %.24s%s\n", buf, len > 24 ? " ..." : "");

        ifindex = get_index_from_cmsg(&m);
        if (args->expected_ifindex) {
                if (args->expected_ifindex != ifindex) {
                        log_error("Device index mismatch: expected %d have %d\n",
                                  args->expected_ifindex, ifindex);
                        return -1;
                }
                log_msg("Device index matches: expected %d have %d\n",
                        args->expected_ifindex, ifindex);
        }

        if (!interactive && server_mode) {
                if (sa->sa_family == AF_INET6) {
                        struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) sa;
                        struct in6_addr *in6 = &s6->sin6_addr;

                        if (IN6_IS_ADDR_V4MAPPED(in6)) {
                                const uint32_t *pa = (uint32_t *) &in6->s6_addr;
                                struct in_addr in4;
                                struct sockaddr_in *sin;

                                sin = (struct sockaddr_in *) addr;
                                pa += 3;
                                in4.s_addr = *pa;
                                sin->sin_addr = in4;
                                sin->sin_family = AF_INET;
                                if (send_msg_cmsg(sd, addr, alen,
                                                  ifindex, AF_INET) < 0)
                                        goto out_err;
                        }
                }
again:
                iov[0].iov_len = len;

                if (args->version == AF_INET6) {
                        struct sockaddr_in6 *s6 = (struct sockaddr_in6 *) sa;

                        if (args->dev) {
                                /* avoid PKTINFO conflicts with bindtodev */
                                if (sendto(sd, buf, len, 0,
                                           (void *) addr, alen) < 0)
                                        goto out_err;
                        } else {
                                /* kernel is allowing scope_id to be set to VRF
                                 * index for LLA. for sends to global address
                                 * reset scope id
                                 */
                                s6->sin6_scope_id = ifindex;
                                if (sendmsg(sd, &m, 0) < 0)
                                        goto out_err;
                        }
                } else {
                        int err;

                        err = sendmsg(sd, &m, 0);
                        if (err < 0) {
                                if (errno == EACCES && try_broadcast) {
                                        try_broadcast = 0;
                                        if (!set_broadcast(sd))
                                                goto again;
                                        errno = EACCES;
                                }
                                goto out_err;
                        }
                }
                log_msg("Sent message:\n");
                log_msg("    %.24s%s\n", buf, len > 24 ? " ..." : "");
        }

        return 1;
out_err:
        log_err_errno("failed to send msg to peer");
        return -1;
}

static int socket_read_stream(int sd)
{
        char buf[1024];
        int len;

        len = read(sd, buf, sizeof(buf)-1);
        if (len == 0) {
                log_msg("client closed connection.\n");
                return 0;
        } else if (len < 0) {
                log_msg("failed to read message\n");
                return -1;
        }

        buf[len] = '\0';
        log_msg("Incoming message:\n");
        log_msg("    %.24s%s\n", buf, len > 24 ? " ..." : "");

        if (!interactive && server_mode) {
                if (write(sd, buf, len) < 0) {
                        log_err_errno("failed to send buf");
                        return -1;
                }
                log_msg("Sent message:\n");
                log_msg("     %.24s%s\n", buf, len > 24 ? " ..." : "");
        }

        return 1;
}

static int socket_read(int sd, struct sock_args *args)
{
        if (args->type == SOCK_STREAM)
                return socket_read_stream(sd);

        return socket_read_dgram(sd, args);
}

static int stdin_to_socket(int sd, int type, void *addr, socklen_t alen)
{
        char buf[1024];
        int len;

        if (fgets(buf, sizeof(buf), stdin) == NULL)
                return 0;

        len = strlen(buf);
        if (type == SOCK_STREAM) {
                if (write(sd, buf, len) < 0) {
                        log_err_errno("failed to send buf");
                        return -1;
                }
        } else {
                int err;

again:
                err = sendto(sd, buf, len, 0, addr, alen);
                if (err < 0) {
                        if (errno == EACCES && try_broadcast) {
                                try_broadcast = 0;
                                if (!set_broadcast(sd))
                                        goto again;
                                errno = EACCES;
                        }
                        log_err_errno("failed to send msg to peer");
                        return -1;
                }
        }
        log_msg("Sent message:\n");
        log_msg("    %.24s%s\n", buf, len > 24 ? " ..." : "");

        return 1;
}

static void set_recv_attr(int sd, int version)
{
        if (version == AF_INET6) {
                set_recvpktinfo_v6(sd);
                set_recverr_v6(sd);
        } else {
                set_pktinfo_v4(sd);
                set_recverr_v4(sd);
        }
}

static int msg_loop(int client, int sd, void *addr, socklen_t alen,
                    struct sock_args *args)
{
        struct timeval timeout = { .tv_sec = prog_timeout }, *ptval = NULL;
        fd_set rfds;
        int nfds;
        int rc;

        if (args->type != SOCK_STREAM)
                set_recv_attr(sd, args->version);

        if (msg) {
                msglen = strlen(msg);

                /* client sends first message */
                if (client) {
                        if (send_msg(sd, addr, alen, args))
                                return 1;
                }
                if (!interactive) {
                        ptval = &timeout;
                        if (!prog_timeout)
                                timeout.tv_sec = 5;
                }
        }

        nfds = interactive ? MAX(fileno(stdin), sd) + 1 : sd + 1;
        while (1) {
                FD_ZERO(&rfds);
                FD_SET(sd, &rfds);
                if (interactive)
                        FD_SET(fileno(stdin), &rfds);

                rc = select(nfds, &rfds, NULL, NULL, ptval);
                if (rc < 0) {
                        if (errno == EINTR)
                                continue;

                        rc = 1;
                        log_err_errno("select failed");
                        break;
                } else if (rc == 0) {
                        log_error("Timed out waiting for response\n");
                        rc = 2;
                        break;
                }

                if (FD_ISSET(sd, &rfds)) {
                        rc = socket_read(sd, args);
                        if (rc < 0) {
                                rc = 1;
                                break;
                        }
                        if (rc == 0)
                                break;
                }

                rc = 0;

                if (FD_ISSET(fileno(stdin), &rfds)) {
                        if (stdin_to_socket(sd, args->type, addr, alen) <= 0)
                                break;
                }

                if (interactive)
                        continue;

                if (iter != -1) {
                        --iter;
                        if (iter == 0)
                                break;
                }

                log_msg("Going into quiet mode\n");
                quiet = 1;

                if (client) {
                        if (send_msg(sd, addr, alen, args)) {
                                rc = 1;
                                break;
                        }
                }
        }

        return rc;
}

static int msock_init(struct sock_args *args, int server)
{
        uint32_t if_addr = htonl(INADDR_ANY);
        struct sockaddr_in laddr = {
                .sin_family = AF_INET,
                .sin_port = htons(args->port),
        };
        int one = 1;
        int sd;

        if (!server && args->has_local_ip)
                if_addr = args->local_addr.in.s_addr;

        sd = socket(PF_INET, SOCK_DGRAM, 0);
        if (sd < 0) {
                log_err_errno("socket");
                return -1;
        }

        if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR,
                       (char *)&one, sizeof(one)) < 0) {
                log_err_errno("Setting SO_REUSEADDR error");
                goto out_err;
        }

        if (setsockopt(sd, SOL_SOCKET, SO_BROADCAST,
                       (char *)&one, sizeof(one)) < 0)
                log_err_errno("Setting SO_BROADCAST error");

        if (set_dsfield(sd, AF_INET, args->dsfield) != 0)
                goto out_err;

        if (server) {
                if (args->server_dontroute && set_dontroute(sd) != 0)
                        goto out_err;
        } else {
                if (args->client_dontroute && set_dontroute(sd) != 0)
                        goto out_err;
        }

        if (args->dev && bind_to_device(sd, args->dev) != 0)
                goto out_err;
        else if (args->use_setsockopt &&
                 set_multicast_if(sd, args->ifindex))
                goto out_err;

        laddr.sin_addr.s_addr = if_addr;

        if (bind(sd, (struct sockaddr *) &laddr, sizeof(laddr)) < 0) {
                log_err_errno("bind failed");
                goto out_err;
        }

        if (server &&
            set_membership(sd, args->grp.s_addr,
                           args->local_addr.in.s_addr, args->ifindex))
                goto out_err;

        return sd;
out_err:
        close(sd);
        return -1;
}

static int msock_server(struct sock_args *args)
{
        return msock_init(args, 1);
}

static int msock_client(struct sock_args *args)
{
        return msock_init(args, 0);
}

static int bind_socket(int sd, struct sock_args *args)
{
        struct sockaddr_in serv_addr = {
                .sin_family = AF_INET,
        };
        struct sockaddr_in6 serv6_addr = {
                .sin6_family = AF_INET6,
        };
        void *addr;
        socklen_t alen;

        if (!args->has_local_ip && args->type == SOCK_RAW)
                return 0;

        switch (args->version) {
        case AF_INET:
                serv_addr.sin_port = htons(args->port);
                serv_addr.sin_addr = args->local_addr.in;
                addr = &serv_addr;
                alen = sizeof(serv_addr);
                break;

        case AF_INET6:
                serv6_addr.sin6_port = htons(args->port);
                serv6_addr.sin6_addr = args->local_addr.in6;
                addr = &serv6_addr;
                alen = sizeof(serv6_addr);
                break;

        default:
                log_error("Invalid address family\n");
                return -1;
        }

        if (bind(sd, addr, alen) < 0) {
                log_err_errno("error binding socket");
                return -1;
        }

        return 0;
}

static int config_xfrm_policy(int sd, struct sock_args *args)
{
        struct xfrm_userpolicy_info policy = {};
        int type = UDP_ENCAP_ESPINUDP;
        int xfrm_af = IP_XFRM_POLICY;
        int level = SOL_IP;

        if (args->type != SOCK_DGRAM) {
                log_error("Invalid socket type. Only DGRAM could be used for XFRM\n");
                return 1;
        }

        policy.action = XFRM_POLICY_ALLOW;
        policy.sel.family = args->version;
        if (args->version == AF_INET6) {
                xfrm_af = IPV6_XFRM_POLICY;
                level = SOL_IPV6;
        }

        policy.dir = XFRM_POLICY_OUT;
        if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
                return 1;

        policy.dir = XFRM_POLICY_IN;
        if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
                return 1;

        if (setsockopt(sd, IPPROTO_UDP, UDP_ENCAP, &type, sizeof(type)) < 0) {
                log_err_errno("Failed to set xfrm encap");
                return 1;
        }

        return 0;
}

static int lsock_init(struct sock_args *args)
{
        long flags;
        int sd;

        sd = socket(args->version, args->type, args->protocol);
        if (sd < 0) {
                log_err_errno("Error opening socket");
                return -1;
        }

        if (set_reuseaddr(sd) != 0)
                goto err;

        if (set_reuseport(sd) != 0)
                goto err;

        if (set_dsfield(sd, args->version, args->dsfield) != 0)
                goto err;

        if (args->server_dontroute && set_dontroute(sd) != 0)
                goto err;

        if (args->dev && bind_to_device(sd, args->dev) != 0)
                goto err;
        else if (args->use_setsockopt &&
                 set_unicast_if(sd, args->ifindex, args->version))
                goto err;

        if (args->use_freebind && set_freebind(sd, args->version))
                goto err;

        if (bind_socket(sd, args))
                goto err;

        if (args->bind_test_only)
                goto out;

        if (args->type == SOCK_STREAM && listen(sd, 1) < 0) {
                log_err_errno("listen failed");
                goto err;
        }

        flags = fcntl(sd, F_GETFL);
        if ((flags < 0) || (fcntl(sd, F_SETFL, flags|O_NONBLOCK) < 0)) {
                log_err_errno("Failed to set non-blocking option");
                goto err;
        }

        if (fcntl(sd, F_SETFD, FD_CLOEXEC) < 0)
                log_err_errno("Failed to set close-on-exec flag");

        if (args->use_xfrm && config_xfrm_policy(sd, args)) {
                log_err_errno("Failed to set xfrm policy");
                goto err;
        }

out:
        return sd;

err:
        close(sd);
        return -1;
}

static void ipc_write(int fd, int message)
{
        /* Not in both_mode, so there's no process to signal */
        if (fd < 0)
                return;

        if (write(fd, &message, sizeof(message)) < 0)
                log_err_errno("Failed to send client status");
}

static int do_server(struct sock_args *args, int ipc_fd)
{
        /* ipc_fd = -1 if no parent process to signal */
        struct timeval timeout = { .tv_sec = prog_timeout }, *ptval = NULL;
        unsigned char addr[sizeof(struct sockaddr_in6)] = {};
        socklen_t alen = sizeof(addr);
        int lsd, csd = -1;

        fd_set rfds;
        int rc;

        if (args->serverns) {
                if (switch_ns(args->serverns)) {
                        log_error("Could not set server netns to %s\n",
                                  args->serverns);
                        goto err_exit;
                }
                log_msg("Switched server netns\n");
        }

        args->dev = args->server_dev;
        args->expected_dev = args->expected_server_dev;
        if (resolve_devices(args) || validate_addresses(args))
                goto err_exit;

        if (prog_timeout)
                ptval = &timeout;

        if (args->has_grp)
                lsd = msock_server(args);
        else
                lsd = lsock_init(args);

        if (lsd < 0)
                goto err_exit;

        if (args->bind_test_only) {
                close(lsd);
                ipc_write(ipc_fd, 1);
                return 0;
        }

        if (args->type != SOCK_STREAM) {
                ipc_write(ipc_fd, 1);
                rc = msg_loop(0, lsd, (void *) addr, alen, args);
                close(lsd);
                return rc;
        }

        if (args->password && tcp_md5_remote(lsd, args)) {
                close(lsd);
                goto err_exit;
        }

        ipc_write(ipc_fd, 1);
        while (1) {
                log_msg("waiting for client connection.\n");
                FD_ZERO(&rfds);
                FD_SET(lsd, &rfds);

                rc = select(lsd+1, &rfds, NULL, NULL, ptval);
                if (rc == 0) {
                        rc = 2;
                        break;
                }

                if (rc < 0) {
                        if (errno == EINTR)
                                continue;

                        log_err_errno("select failed");
                        break;
                }

                if (FD_ISSET(lsd, &rfds)) {

                        csd = accept(lsd, (void *) addr, &alen);
                        if (csd < 0) {
                                log_err_errno("accept failed");
                                break;
                        }

                        rc = show_sockstat(csd, args);
                        if (rc)
                                break;

                        rc = check_device(csd, args);
                        if (rc)
                                break;
                }

                rc = msg_loop(0, csd, (void *) addr, alen, args);
                close(csd);

                if (!interactive)
                        break;
        }

        close(lsd);

        return rc;
err_exit:
        ipc_write(ipc_fd, 0);
        return 1;
}

static int wait_for_connect(int sd)
{
        struct timeval _tv = { .tv_sec = prog_timeout }, *tv = NULL;
        fd_set wfd;
        int val = 0, sz = sizeof(val);
        int rc;

        FD_ZERO(&wfd);
        FD_SET(sd, &wfd);

        if (prog_timeout)
                tv = &_tv;

        rc = select(FD_SETSIZE, NULL, &wfd, NULL, tv);
        if (rc == 0) {
                log_error("connect timed out\n");
                return -2;
        } else if (rc < 0) {
                log_err_errno("select failed");
                return -3;
        }

        if (getsockopt(sd, SOL_SOCKET, SO_ERROR, &val, (socklen_t *)&sz) < 0) {
                log_err_errno("getsockopt(SO_ERROR) failed");
                return -4;
        }

        if (val != 0) {
                log_error("connect failed: %d: %s\n", val, strerror(val));
                return -1;
        }

        return 0;
}

static int connectsock(void *addr, socklen_t alen, struct sock_args *args)
{
        int sd, rc = -1;
        long flags;

        sd = socket(args->version, args->type, args->protocol);
        if (sd < 0) {
                log_err_errno("Failed to create socket");
                return -1;
        }

        flags = fcntl(sd, F_GETFL);
        if ((flags < 0) || (fcntl(sd, F_SETFL, flags|O_NONBLOCK) < 0)) {
                log_err_errno("Failed to set non-blocking option");
                goto err;
        }

        if (set_reuseport(sd) != 0)
                goto err;

        if (set_dsfield(sd, args->version, args->dsfield) != 0)
                goto err;

        if (args->client_dontroute && set_dontroute(sd) != 0)
                goto err;

        if (args->dev && bind_to_device(sd, args->dev) != 0)
                goto err;
        else if (args->use_setsockopt &&
                 set_unicast_if(sd, args->ifindex, args->version))
                goto err;

        if (args->has_local_ip && bind_socket(sd, args))
                goto err;

        if (args->type != SOCK_STREAM && !args->datagram_connect)
                goto out;

        if (args->password && tcp_md5sig(sd, addr, alen, args))
                goto err;

        if (args->bind_test_only)
                goto out;

        if (connect(sd, addr, alen) < 0) {
                if (errno != EINPROGRESS) {
                        log_err_errno("Failed to connect to remote host");
                        rc = -1;
                        goto err;
                }
                rc = wait_for_connect(sd);
                if (rc < 0)
                        goto err;
        }
out:
        return sd;

err:
        close(sd);
        return rc;
}

static int do_client(struct sock_args *args)
{
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
        };
        struct sockaddr_in6 sin6 = {
                .sin6_family = AF_INET6,
        };
        void *addr;
        int alen;
        int rc = 0;
        int sd;

        if (!args->has_remote_ip && !args->has_grp) {
                fprintf(stderr, "remote IP or multicast group not given\n");
                return 1;
        }

        if (args->clientns) {
                if (switch_ns(args->clientns)) {
                        log_error("Could not set client netns to %s\n",
                                  args->clientns);
                        return 1;
                }
                log_msg("Switched client netns\n");
        }

        args->local_addr_str = args->client_local_addr_str;
        if (resolve_devices(args) || validate_addresses(args))
                return 1;

        if ((args->use_setsockopt || args->use_cmsg) && !args->ifindex) {
                fprintf(stderr, "Device binding not specified\n");
                return 1;
        }
        if (args->use_setsockopt || args->use_cmsg)
                args->dev = NULL;

        switch (args->version) {
        case AF_INET:
                sin.sin_port = htons(args->port);
                if (args->has_grp)
                        sin.sin_addr = args->grp;
                else
                        sin.sin_addr = args->remote_addr.in;
                addr = &sin;
                alen = sizeof(sin);
                break;
        case AF_INET6:
                sin6.sin6_port = htons(args->port);
                sin6.sin6_addr = args->remote_addr.in6;
                sin6.sin6_scope_id = args->scope_id;
                addr = &sin6;
                alen = sizeof(sin6);
                break;
        }

        args->password = args->client_pw;

        if (args->has_grp)
                sd = msock_client(args);
        else
                sd = connectsock(addr, alen, args);

        if (sd < 0)
                return -sd;

        if (args->bind_test_only)
                goto out;

        if (args->type == SOCK_STREAM) {
                rc = show_sockstat(sd, args);
                if (rc != 0)
                        goto out;
        }

        rc = msg_loop(1, sd, addr, alen, args);

out:
        close(sd);

        return rc;
}

static char *random_msg(int len)
{
        int i, n = 0, olen = len + 1;
        char *m;

        if (len <= 0)
                return NULL;

        m = malloc(olen);
        if (!m)
                return NULL;

        while (len > 26) {
                i = snprintf(m + n, olen - n, "%.26s",
                             "abcdefghijklmnopqrstuvwxyz");
                n += i;
                len -= i;
        }

        snprintf(m + n, olen - n, "%.*s", len,
             "abcdefghijklmnopqrstuvwxyz");
        return m;
}

static int ipc_child(int fd, struct sock_args *args)
{
        char *outbuf, *errbuf;
        int rc = 1;

        outbuf = malloc(4096);
        errbuf = malloc(4096);
        if (!outbuf || !errbuf) {
                fprintf(stderr, "server: Failed to allocate buffers for stdout and stderr\n");
                goto out;
        }

        setbuffer(stdout, outbuf, 4096);
        setbuffer(stderr, errbuf, 4096);

        server_mode = 1; /* to tell log_msg in case we are in both_mode */

        /* when running in both mode, address validation applies
         * solely to client side
         */
        args->has_expected_laddr = 0;
        args->has_expected_raddr = 0;

        rc = do_server(args, fd);

out:
        free(outbuf);
        free(errbuf);

        return rc;
}

static int ipc_parent(int cpid, int fd, struct sock_args *args)
{
        int client_status;
        int status;
        int buf;

        /* do the client-side function here in the parent process,
         * waiting to be told when to continue
         */
        if (read(fd, &buf, sizeof(buf)) <= 0) {
                log_err_errno("Failed to read IPC status from pipe");
                return 1;
        }
        if (!buf) {
                log_error("Server failed; can not continue\n");
                return 1;
        }
        log_msg("Server is ready\n");

        client_status = do_client(args);
        log_msg("parent is done!\n");

        if (kill(cpid, 0) == 0)
                kill(cpid, SIGKILL);

        wait(&status);
        return client_status;
}

#define GETOPT_STR  "sr:l:c:Q:p:t:g:P:DRn:M:X:m:d:I:BN:O:SUCi6xL:0:1:2:3:Fbqf"
#define OPT_FORCE_BIND_KEY_IFINDEX 1001
#define OPT_NO_BIND_KEY_IFINDEX 1002
#define OPT_CLIENT_DONTROUTE 1003
#define OPT_SERVER_DONTROUTE 1004

static struct option long_opts[] = {
        {"force-bind-key-ifindex", 0, 0, OPT_FORCE_BIND_KEY_IFINDEX},
        {"no-bind-key-ifindex", 0, 0, OPT_NO_BIND_KEY_IFINDEX},
        {"client-dontroute", 0, 0, OPT_CLIENT_DONTROUTE},
        {"server-dontroute", 0, 0, OPT_SERVER_DONTROUTE},
        {0, 0, 0, 0}
};

static void print_usage(char *prog)
{
        printf(
        "usage: %s OPTS\n"
        "Required:\n"
        "    -r addr       remote address to connect to (client mode only)\n"
        "    -p port       port to connect to (client mode)/listen on (server mode)\n"
        "                  (default: %d)\n"
        "    -s            server mode (default: client mode)\n"
        "    -t            timeout seconds (default: none)\n"
        "\n"
        "Optional:\n"
        "    -B            do both client and server via fork and IPC\n"
        "    -N ns         set client to network namespace ns (requires root)\n"
        "    -O ns         set server to network namespace ns (requires root)\n"
        "    -F            Restart server loop\n"
        "    -6            IPv6 (default is IPv4)\n"
        "    -P proto      protocol for socket: icmp, ospf (default: none)\n"
        "    -D|R          datagram (D) / raw (R) socket (default stream)\n"
        "    -l addr       local address to bind to in server mode\n"
        "    -c addr       local address to bind to in client mode\n"
        "    -Q dsfield    DS Field value of the socket (the IP_TOS or\n"
        "                  IPV6_TCLASS socket option)\n"
        "    -x            configure XFRM policy on socket\n"
        "\n"
        "    -d dev        bind socket to given device name\n"
        "    -I dev        bind socket to given device name - server mode\n"
        "    -S            use setsockopt (IP_UNICAST_IF or IP_MULTICAST_IF)\n"
        "                  to set device binding\n"
        "    -U            Use connect() and send() for datagram sockets\n"
        "    -f            bind socket with the IP[V6]_FREEBIND option\n"
        "    -C            use cmsg and IP_PKTINFO to specify device binding\n"
        "\n"
        "    -L len        send random message of given length\n"
        "    -n num        number of times to send message\n"
        "\n"
        "    -M password   use MD5 sum protection\n"
        "    -X password   MD5 password for client mode\n"
        "    -m prefix/len prefix and length to use for MD5 key\n"
        "    --no-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX off\n"
        "    --force-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX on\n"
        "        (default: only if -I is passed)\n"
        "    --client-dontroute: don't use gateways for client socket: send\n"
        "                        packets only if destination is on link (see\n"
        "                        SO_DONTROUTE in socket(7))\n"
        "    --server-dontroute: don't use gateways for server socket: send\n"
        "                        packets only if destination is on link (see\n"
        "                        SO_DONTROUTE in socket(7))\n"
        "\n"
        "    -g grp        multicast group (e.g., 239.1.1.1)\n"
        "    -i            interactive mode (default is echo and terminate)\n"
        "\n"
        "    -0 addr       Expected local address\n"
        "    -1 addr       Expected remote address\n"
        "    -2 dev        Expected device name (or index) to receive packet\n"
        "    -3 dev        Expected device name (or index) to receive packets - server mode\n"
        "\n"
        "    -b            Bind test only.\n"
        "    -q            Be quiet. Run test without printing anything.\n"
        , prog, DEFAULT_PORT);
}

int main(int argc, char *argv[])
{
        struct sock_args args = {
                .version = AF_INET,
                .type    = SOCK_STREAM,
                .port    = DEFAULT_PORT,
        };
        struct protoent *pe;
        int both_mode = 0;
        unsigned int tmp;
        int forever = 0;
        int fd[2];
        int cpid;

        /* process inputs */
        extern char *optarg;
        int rc = 0;

        /*
         * process input args
         */

        while ((rc = getopt_long(argc, argv, GETOPT_STR, long_opts, NULL)) != -1) {
                switch (rc) {
                case 'B':
                        both_mode = 1;
                        break;
                case 's':
                        server_mode = 1;
                        break;
                case 'F':
                        forever = 1;
                        break;
                case 'l':
                        args.has_local_ip = 1;
                        args.local_addr_str = optarg;
                        break;
                case 'r':
                        args.has_remote_ip = 1;
                        args.remote_addr_str = optarg;
                        break;
                case 'c':
                        args.has_local_ip = 1;
                        args.client_local_addr_str = optarg;
                        break;
                case 'Q':
                        if (str_to_uint(optarg, 0, 255, &tmp) != 0) {
                                fprintf(stderr, "Invalid DS Field\n");
                                return 1;
                        }
                        args.dsfield = tmp;
                        break;
                case 'p':
                        if (str_to_uint(optarg, 1, 65535, &tmp) != 0) {
                                fprintf(stderr, "Invalid port\n");
                                return 1;
                        }
                        args.port = (unsigned short) tmp;
                        break;
                case 't':
                        if (str_to_uint(optarg, 0, INT_MAX,
                                        &prog_timeout) != 0) {
                                fprintf(stderr, "Invalid timeout\n");
                                return 1;
                        }
                        break;
                case 'D':
                        args.type = SOCK_DGRAM;
                        break;
                case 'R':
                        args.type = SOCK_RAW;
                        args.port = 0;
                        if (!args.protocol)
                                args.protocol = IPPROTO_RAW;
                        break;
                case 'P':
                        pe = getprotobyname(optarg);
                        if (pe) {
                                args.protocol = pe->p_proto;
                        } else {
                                if (str_to_uint(optarg, 0, 0xffff, &tmp) != 0) {
                                        fprintf(stderr, "Invalid protocol\n");
                                        return 1;
                                }
                                args.protocol = tmp;
                        }
                        break;
                case 'n':
                        iter = atoi(optarg);
                        break;
                case 'N':
                        args.clientns = optarg;
                        break;
                case 'O':
                        args.serverns = optarg;
                        break;
                case 'L':
                        msg = random_msg(atoi(optarg));
                        break;
                case 'M':
                        args.password = optarg;
                        break;
                case OPT_FORCE_BIND_KEY_IFINDEX:
                        args.bind_key_ifindex = 1;
                        break;
                case OPT_NO_BIND_KEY_IFINDEX:
                        args.bind_key_ifindex = -1;
                        break;
                case OPT_CLIENT_DONTROUTE:
                        args.client_dontroute = 1;
                        break;
                case OPT_SERVER_DONTROUTE:
                        args.server_dontroute = 1;
                        break;
                case 'X':
                        args.client_pw = optarg;
                        break;
                case 'm':
                        args.md5_prefix_str = optarg;
                        break;
                case 'S':
                        args.use_setsockopt = 1;
                        break;
                case 'f':
                        args.use_freebind = 1;
                        break;
                case 'C':
                        args.use_cmsg = 1;
                        break;
                case 'd':
                        args.dev = optarg;
                        break;
                case 'I':
                        args.server_dev = optarg;
                        break;
                case 'i':
                        interactive = 1;
                        break;
                case 'g':
                        args.has_grp = 1;
                        if (convert_addr(&args, optarg, ADDR_TYPE_MCAST) < 0)
                                return 1;
                        args.type = SOCK_DGRAM;
                        break;
                case '6':
                        args.version = AF_INET6;
                        break;
                case 'b':
                        args.bind_test_only = 1;
                        break;
                case '0':
                        args.has_expected_laddr = 1;
                        args.expected_laddr_str = optarg;
                        break;
                case '1':
                        args.has_expected_raddr = 1;
                        args.expected_raddr_str = optarg;
                        break;
                case '2':
                        args.expected_dev = optarg;
                        break;
                case '3':
                        args.expected_server_dev = optarg;
                        break;
                case 'q':
                        quiet = 1;
                        break;
                case 'x':
                        args.use_xfrm = 1;
                        break;
                case 'U':
                        args.datagram_connect = 1;
                        break;
                default:
                        print_usage(argv[0]);
                        return 1;
                }
        }

        if (args.password &&
            ((!args.has_remote_ip && !args.md5_prefix_str) ||
              args.type != SOCK_STREAM)) {
                log_error("MD5 passwords apply to TCP only and require a remote ip for the password\n");
                return 1;
        }

        if (args.md5_prefix_str && !args.password) {
                log_error("Prefix range for MD5 protection specified without a password\n");
                return 1;
        }

        if (iter == 0) {
                fprintf(stderr, "Invalid number of messages to send\n");
                return 1;
        }

        if (args.type == SOCK_STREAM && !args.protocol)
                args.protocol = IPPROTO_TCP;
        if (args.type == SOCK_DGRAM && !args.protocol)
                args.protocol = IPPROTO_UDP;

        if ((args.type == SOCK_STREAM || args.type == SOCK_DGRAM) &&
             args.port == 0) {
                fprintf(stderr, "Invalid port number\n");
                return 1;
        }

        if ((both_mode || !server_mode) && !args.has_grp &&
            !args.has_remote_ip && !args.has_local_ip) {
                fprintf(stderr,
                        "Local (server mode) or remote IP (client IP) required\n");
                return 1;
        }

        if (interactive) {
                prog_timeout = 0;
                msg = NULL;
        }

        if (both_mode) {
                if (pipe(fd) < 0) {
                        perror("pipe");
                        exit(1);
                }

                cpid = fork();
                if (cpid < 0) {
                        perror("fork");
                        exit(1);
                }
                if (cpid)
                        return ipc_parent(cpid, fd[0], &args);

                return ipc_child(fd[1], &args);
        }

        if (server_mode) {
                do {
                        rc = do_server(&args, -1);
                } while (forever);

                return rc;
        }
        return do_client(&args);
}