/*
 * ng_cisco.c
 */

/*-
 * Copyright (c) 1996-1999 Whistle Communications, Inc.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Author: Julian Elischer <julian@freebsd.org>
 * $Whistle: ng_cisco.c,v 1.25 1999/11/01 09:24:51 julian Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_cisco.h>

#define CISCO_MULTICAST         0x8f    /* Cisco multicast address */
#define CISCO_UNICAST           0x0f    /* Cisco unicast address */
#define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
#define CISCO_ADDR_REQ          0       /* Cisco address request */
#define CISCO_ADDR_REPLY        1       /* Cisco address reply */
#define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */

#define KEEPALIVE_SECS          10

struct cisco_header {
        uint8_t  address;
        uint8_t  control;
        uint16_t protocol;
} __packed;

#define CISCO_HEADER_LEN        sizeof (struct cisco_header)

struct cisco_packet {
        uint32_t type;
        uint32_t par1;
        uint32_t par2;
        uint16_t rel;
        uint16_t time0;
        uint16_t time1;
} __packed;

#define CISCO_PACKET_LEN (sizeof(struct cisco_packet))

struct protoent {
        hook_p  hook;           /* the hook for this proto */
        uint16_t af;            /* address family, -1 = downstream */
};

struct cisco_priv {
        uint32_t local_seq;
        uint32_t remote_seq;
        uint32_t seqRetries;    /* how many times we've been here throwing out
                                 * the same sequence number without ack */
        node_p  node;
        struct callout handle;
        struct protoent downstream;
        struct protoent inet;           /* IP information */
        struct in_addr localip;
        struct in_addr localmask;
        struct protoent inet6;          /* IPv6 information */
        struct protoent atalk;          /* AppleTalk information */
        struct protoent ipx;            /* IPX information */
};
typedef struct cisco_priv *sc_p;

/* Netgraph methods */
static ng_constructor_t         cisco_constructor;
static ng_rcvmsg_t              cisco_rcvmsg;
static ng_shutdown_t            cisco_shutdown;
static ng_newhook_t             cisco_newhook;
static ng_rcvdata_t             cisco_rcvdata;
static ng_disconnect_t          cisco_disconnect;

/* Other functions */
static int      cisco_input(sc_p sc, item_p item);
static void     cisco_keepalive(node_p node, hook_p hook, void *arg1, int arg2);
static int      cisco_send(sc_p sc, int type, long par1, long par2);
static void     cisco_notify(sc_p sc, uint32_t cmd);

/* Parse type for struct ng_cisco_ipaddr */
static const struct ng_parse_struct_field ng_cisco_ipaddr_type_fields[]
        = NG_CISCO_IPADDR_TYPE_INFO;
static const struct ng_parse_type ng_cisco_ipaddr_type = {
        &ng_parse_struct_type,
        &ng_cisco_ipaddr_type_fields
};

/* Parse type for struct ng_async_stat */
static const struct ng_parse_struct_field ng_cisco_stats_type_fields[]
        = NG_CISCO_STATS_TYPE_INFO;
static const struct ng_parse_type ng_cisco_stats_type = {
        &ng_parse_struct_type,
        &ng_cisco_stats_type_fields
};

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_cisco_cmdlist[] = {
        {
          NGM_CISCO_COOKIE,
          NGM_CISCO_SET_IPADDR,
          "setipaddr",
          &ng_cisco_ipaddr_type,
          NULL
        },
        {
          NGM_CISCO_COOKIE,
          NGM_CISCO_GET_IPADDR,
          "getipaddr",
          NULL,
          &ng_cisco_ipaddr_type
        },
        {
          NGM_CISCO_COOKIE,
          NGM_CISCO_GET_STATUS,
          "getstats",
          NULL,
          &ng_cisco_stats_type
        },
        { 0 }
};

/* Node type */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_CISCO_NODE_TYPE,
        .constructor =  cisco_constructor,
        .rcvmsg =       cisco_rcvmsg,
        .shutdown =     cisco_shutdown,
        .newhook =      cisco_newhook,
        .rcvdata =      cisco_rcvdata,
        .disconnect =   cisco_disconnect,
        .cmdlist =      ng_cisco_cmdlist,
};
NETGRAPH_INIT(cisco, &typestruct);

/*
 * Node constructor
 */
static int
cisco_constructor(node_p node)
{
        sc_p sc;

        sc = malloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);

        ng_callout_init(&sc->handle);
        NG_NODE_SET_PRIVATE(node, sc);
        sc->node = node;

        /* Initialise the varous protocol hook holders */
        sc->downstream.af = 0xffff;
        sc->inet.af = AF_INET;
        sc->inet6.af = AF_INET6;
        sc->atalk.af = AF_APPLETALK;
        sc->ipx.af = AF_IPX;
        return (0);
}

/*
 * Check new hook
 */
static int
cisco_newhook(node_p node, hook_p hook, const char *name)
{
        const sc_p sc = NG_NODE_PRIVATE(node);

        if (strcmp(name, NG_CISCO_HOOK_DOWNSTREAM) == 0) {
                sc->downstream.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &sc->downstream);

                /* Start keepalives */
                ng_callout(&sc->handle, node, NULL, (hz * KEEPALIVE_SECS),
                    &cisco_keepalive, (void *)sc, 0);
        } else if (strcmp(name, NG_CISCO_HOOK_INET) == 0) {
                sc->inet.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &sc->inet);
        } else if (strcmp(name, NG_CISCO_HOOK_INET6) == 0) {
                sc->inet6.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &sc->inet6);
        } else if (strcmp(name, NG_CISCO_HOOK_APPLETALK) == 0) {
                sc->atalk.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &sc->atalk);
        } else if (strcmp(name, NG_CISCO_HOOK_IPX) == 0) {
                sc->ipx.hook = hook;
                NG_HOOK_SET_PRIVATE(hook, &sc->ipx);
        } else if (strcmp(name, NG_CISCO_HOOK_DEBUG) == 0) {
                NG_HOOK_SET_PRIVATE(hook, NULL);        /* unimplemented */
        } else
                return (EINVAL);
        return 0;
}

/*
 * Receive control message.
 */
static int
cisco_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        struct ng_mesg *msg;
        const sc_p sc = NG_NODE_PRIVATE(node);
        struct ng_mesg *resp = NULL;
        int error = 0;

        NGI_GET_MSG(item, msg);
        switch (msg->header.typecookie) {
        case NGM_GENERIC_COOKIE:
                switch (msg->header.cmd) {
                case NGM_TEXT_STATUS:
                    {
                        char *arg;
                        int pos;

                        NG_MKRESPONSE(resp, msg, NG_TEXTRESPONSE, M_NOWAIT);
                        if (resp == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        arg = (char *) resp->data;
                        pos = sprintf(arg,
                          "keepalive period: %d sec; ", KEEPALIVE_SECS);
                        pos += sprintf(arg + pos,
                          "unacknowledged keepalives: %d", sc->seqRetries);
                        resp->header.arglen = pos + 1;
                        break;
                    }
                default:
                        error = EINVAL;
                        break;
                }
                break;
        case NGM_CISCO_COOKIE:
                switch (msg->header.cmd) {
                case NGM_CISCO_GET_IPADDR:      /* could be a late reply! */
                        if ((msg->header.flags & NGF_RESP) == 0) {
                                struct in_addr *ips;

                                NG_MKRESPONSE(resp, msg,
                                    2 * sizeof(*ips), M_NOWAIT);
                                if (!resp) {
                                        error = ENOMEM;
                                        break;
                                }
                                ips = (struct in_addr *) resp->data;
                                ips[0] = sc->localip;
                                ips[1] = sc->localmask;
                                break;
                        }
                        /* FALLTHROUGH */       /* ...if it's a reply */
                case NGM_CISCO_SET_IPADDR:
                    {
                        struct in_addr *const ips = (struct in_addr *)msg->data;

                        if (msg->header.arglen < 2 * sizeof(*ips)) {
                                error = EINVAL;
                                break;
                        }
                        sc->localip = ips[0];
                        sc->localmask = ips[1];
                        break;
                    }
                case NGM_CISCO_GET_STATUS:
                    {
                        struct ng_cisco_stats *stat;

                        NG_MKRESPONSE(resp, msg, sizeof(*stat), M_NOWAIT);
                        if (!resp) {
                                error = ENOMEM;
                                break;
                        }
                        stat = (struct ng_cisco_stats *)resp->data;
                        stat->seqRetries = sc->seqRetries;
                        stat->keepAlivePeriod = KEEPALIVE_SECS;
                        break;
                    }
                default:
                        error = EINVAL;
                        break;
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        NG_RESPOND_MSG(error, node, item, resp);
        NG_FREE_MSG(msg);
        return (error);
}

/*
 * Receive data
 */
static int
cisco_rcvdata(hook_p hook, item_p item)
{
        const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        struct protoent *pep;
        struct cisco_header *h;
        struct mbuf *m;
        int error = 0;

        if ((pep = NG_HOOK_PRIVATE(hook)) == NULL)
                goto out;

        /* If it came from our downlink, deal with it separately */
        if (pep->af == 0xffff)
                return (cisco_input(sc, item));

        /* OK so it came from a protocol, heading out. Prepend general data
           packet header. For now, IP,IPX only  */
        NGI_GET_M(item, m);
        M_PREPEND(m, CISCO_HEADER_LEN, M_NOWAIT);
        if (!m) {
                error = ENOBUFS;
                goto out;
        }
        NGI_M(item) = m;
        h = mtod(m, struct cisco_header *);
        h->address = CISCO_UNICAST;
        h->control = 0;

        switch (pep->af) {
        case AF_INET:           /* Internet Protocol */
                h->protocol = htons(ETHERTYPE_IP);
                break;
        case AF_INET6:
                h->protocol = htons(ETHERTYPE_IPV6);
                break;
        case AF_APPLETALK:      /* AppleTalk Protocol */
                h->protocol = htons(ETHERTYPE_AT);
                break;
        case AF_IPX:            /* Novell IPX Protocol */
                h->protocol = htons(ETHERTYPE_IPX);
                break;
        default:
                error = EAFNOSUPPORT;
                goto out;
        }

        /* Send it */
        NG_FWD_NEW_DATA(error, item,  sc->downstream.hook, m);
        return (error);

out:
        NG_FREE_ITEM(item);
        return (error);
}

/*
 * Shutdown node
 */
static int
cisco_shutdown(node_p node)
{
        const sc_p sc = NG_NODE_PRIVATE(node);

        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(sc->node);
        free(sc, M_NETGRAPH);
        return (0);
}

/*
 * Disconnection of a hook
 *
 * For this type, removal of the last link destroys the node
 */
static int
cisco_disconnect(hook_p hook)
{
        const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        struct protoent *pep;

        /* Check it's not the debug hook */
        if ((pep = NG_HOOK_PRIVATE(hook))) {
                pep->hook = NULL;
                if (pep->af == 0xffff)
                        /* If it is the downstream hook, stop the timers */
                        ng_uncallout(&sc->handle, NG_HOOK_NODE(hook));
        }

        /* If no more hooks, remove the node */
        if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
        && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
                ng_rmnode_self(NG_HOOK_NODE(hook));
        return (0);
}

/*
 * Receive data
 */
static int
cisco_input(sc_p sc, item_p item)
{
        const struct cisco_header *h;
        struct cisco_header hdrbuf;
        struct protoent *pep;
        struct mbuf *m;
        int error = 0;

        /* Get data */
        m = NGI_M(item);

        /* Sanity check header length */
        if (m->m_pkthdr.len < sizeof(*h)) {
                error = EINVAL;
                goto drop;
        }

        /* Get cisco header */
        if (m->m_len >= sizeof(*h))                     /* the common case */
                h = mtod(m, const struct cisco_header *);
        else {
                m_copydata(m, 0, sizeof(*h), (caddr_t)&hdrbuf);
                h = &hdrbuf;
        }
        m_adj(m, sizeof(*h));

        /* Check header address */
        switch (h->address) {
        default:                /* Invalid Cisco packet. */
                goto drop;
        case CISCO_UNICAST:
        case CISCO_MULTICAST:
                /* Don't check the control field here (RFC 1547). */
                switch (ntohs(h->protocol)) {
                default:
                        goto drop;
                case CISCO_KEEPALIVE:
                    {
                        const struct cisco_packet *p;
                        struct cisco_packet pktbuf;

                        /* Sanity check packet length */
                        if (m->m_pkthdr.len < sizeof(*p)) {
                                error = EINVAL;
                                goto drop;
                        }

                        /* Get cisco packet */
                        if (m->m_len >= sizeof(*p))     /* the common case */
                                p = mtod(m, const struct cisco_packet *);
                        else {
                                m_copydata(m, 0, sizeof(*p), (caddr_t)&pktbuf);
                                p = &pktbuf;
                        }

                        /* Check packet type */
                        switch (ntohl(p->type)) {
                        default:
                                log(LOG_WARNING,
                                    "cisco: unknown cisco packet type: 0x%lx\n",
                                       (long)ntohl(p->type));
                                break;
                        case CISCO_ADDR_REPLY:
                                /* Reply on address request, ignore */
                                break;
                        case CISCO_KEEPALIVE_REQ:
                                sc->remote_seq = ntohl(p->par1);
                                if (sc->local_seq == ntohl(p->par2)) {
                                        sc->local_seq++;
                                        if (sc->seqRetries > 1)
                                                cisco_notify(sc, NGM_LINK_IS_UP);
                                        sc->seqRetries = 0;
                                }
                                break;
                        case CISCO_ADDR_REQ:
                            {
                                struct ng_mesg *msg;
                                int dummy_error = 0;

                                /* Ask inet peer for IP address information */
                                if (sc->inet.hook == NULL)
                                        goto nomsg;
                                NG_MKMESSAGE(msg, NGM_CISCO_COOKIE,
                                    NGM_CISCO_GET_IPADDR, 0, M_NOWAIT);
                                if (msg == NULL)
                                        goto nomsg;
                                NG_SEND_MSG_HOOK(dummy_error,
                                    sc->node, msg, sc->inet.hook, 0);
                /*
                 * XXX Now maybe we should set a flag telling
                 * our receiver to send this message when the response comes in
                 * instead of now when the data may be bad.
                 */
                nomsg:
                                /* Send reply to peer device */
                                error = cisco_send(sc, CISCO_ADDR_REPLY,
                                            ntohl(sc->localip.s_addr),
                                            ntohl(sc->localmask.s_addr));
                                break;
                            }
                        }
                        goto drop;
                    }
                case ETHERTYPE_IP:
                        pep = &sc->inet;
                        break;
                case ETHERTYPE_IPV6:
                        pep = &sc->inet6;
                        break;
                case ETHERTYPE_AT:
                        pep = &sc->atalk;
                        break;
                case ETHERTYPE_IPX:
                        pep = &sc->ipx;
                        break;
                }
                break;
        }

        /* Drop if payload is empty */
        if (m->m_pkthdr.len == 0) {
                error = EINVAL;
                goto drop;
        }

        /* Send it on */
        if (pep->hook == NULL)
                goto drop;
        NG_FWD_NEW_DATA(error, item, pep->hook, m);
        return (error);

drop:
        NG_FREE_ITEM(item);
        return (error);
}

/*
 * Send keepalive packets, every 10 seconds.
 */
static void
cisco_keepalive(node_p node, hook_p hook, void *arg1, int arg2)
{
        const sc_p sc = arg1;

        cisco_send(sc, CISCO_KEEPALIVE_REQ, sc->local_seq, sc->remote_seq);
        if (sc->seqRetries++ > 1)
                cisco_notify(sc, NGM_LINK_IS_DOWN);
        ng_callout(&sc->handle, node, NULL, (hz * KEEPALIVE_SECS),
            &cisco_keepalive, (void *)sc, 0);
}

/*
 * Send Cisco keepalive packet.
 */
static int
cisco_send(sc_p sc, int type, long par1, long par2)
{
        struct cisco_header *h;
        struct cisco_packet *ch;
        struct mbuf *m;
        struct timeval time;
        uint32_t t;
        int     error = 0;

        getmicrouptime(&time);

        MGETHDR(m, M_NOWAIT, MT_DATA);
        if (!m)
                return (ENOBUFS);

        t = time.tv_sec * 1000 + time.tv_usec / 1000;
        m->m_pkthdr.len = m->m_len = CISCO_HEADER_LEN + CISCO_PACKET_LEN;
        m->m_pkthdr.rcvif = 0;

        h = mtod(m, struct cisco_header *);
        h->address = CISCO_MULTICAST;
        h->control = 0;
        h->protocol = htons(CISCO_KEEPALIVE);

        ch = (struct cisco_packet *) (h + 1);
        ch->type = htonl(type);
        ch->par1 = htonl(par1);
        ch->par2 = htonl(par2);
        ch->rel = -1;
        ch->time0 = htons((uint16_t) (t >> 16));
        ch->time1 = htons((uint16_t) t);

        NG_SEND_DATA_ONLY(error, sc->downstream.hook, m);
        return (error);
}

/*
 * Send linkstate to upstream node.
 */
static void
cisco_notify(sc_p sc, uint32_t cmd)
{
        struct ng_mesg *msg;
        int dummy_error = 0;

        if (sc->inet.hook == NULL) /* nothing to notify */
                return;
                
        NG_MKMESSAGE(msg, NGM_FLOW_COOKIE, cmd, 0, M_NOWAIT);
        if (msg != NULL)
                NG_SEND_MSG_HOOK(dummy_error, sc->node, msg, sc->inet.hook, 0);
}