// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ip_vs_proto.c: transport protocol load balancing support for IPVS
 *
 * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
 *              Julian Anastasov <ja@ssi.bg>
 *
 * Changes:
 */

#define pr_fmt(fmt) "IPVS: " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/gfp.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <linux/stat.h>
#include <linux/proc_fs.h>

#include <net/ip_vs.h>


/*
 * IPVS protocols can only be registered/unregistered when the ipvs
 * module is loaded/unloaded, so no lock is needed in accessing the
 * ipvs protocol table.
 */

#define IP_VS_PROTO_TAB_SIZE            32      /* must be power of 2 */
#define IP_VS_PROTO_HASH(proto)         ((proto) & (IP_VS_PROTO_TAB_SIZE-1))

static struct ip_vs_protocol *ip_vs_proto_table[IP_VS_PROTO_TAB_SIZE];

/* States for conn templates: NONE or words separated with ",", max 15 chars */
static const char *ip_vs_ctpl_state_name_table[IP_VS_CTPL_S_LAST] = {
        [IP_VS_CTPL_S_NONE]                     = "NONE",
        [IP_VS_CTPL_S_ASSURED]                  = "ASSURED",
};

/*
 *      register an ipvs protocol
 */
static int __used __init register_ip_vs_protocol(struct ip_vs_protocol *pp)
{
        unsigned int hash = IP_VS_PROTO_HASH(pp->protocol);

        pp->next = ip_vs_proto_table[hash];
        ip_vs_proto_table[hash] = pp;

        if (pp->init != NULL)
                pp->init(pp);

        return 0;
}

/*
 *      register an ipvs protocols netns related data
 */
static int
register_ip_vs_proto_netns(struct netns_ipvs *ipvs, struct ip_vs_protocol *pp)
{
        unsigned int hash = IP_VS_PROTO_HASH(pp->protocol);
        struct ip_vs_proto_data *pd =
                        kzalloc_obj(struct ip_vs_proto_data);

        if (!pd)
                return -ENOMEM;

        pd->pp = pp;    /* For speed issues */
        pd->next = ipvs->proto_data_table[hash];
        ipvs->proto_data_table[hash] = pd;
        atomic_set(&pd->appcnt, 0);     /* Init app counter */

        if (pp->init_netns != NULL) {
                int ret = pp->init_netns(ipvs, pd);
                if (ret) {
                        /* unlink an free proto data */
                        ipvs->proto_data_table[hash] = pd->next;
                        kfree(pd);
                        return ret;
                }
        }

        return 0;
}

/*
 *      unregister an ipvs protocol
 */
static int unregister_ip_vs_protocol(struct ip_vs_protocol *pp)
{
        struct ip_vs_protocol **pp_p;
        unsigned int hash = IP_VS_PROTO_HASH(pp->protocol);

        pp_p = &ip_vs_proto_table[hash];
        for (; *pp_p; pp_p = &(*pp_p)->next) {
                if (*pp_p == pp) {
                        *pp_p = pp->next;
                        if (pp->exit != NULL)
                                pp->exit(pp);
                        return 0;
                }
        }

        return -ESRCH;
}

/*
 *      unregister an ipvs protocols netns data
 */
static int
unregister_ip_vs_proto_netns(struct netns_ipvs *ipvs, struct ip_vs_proto_data *pd)
{
        struct ip_vs_proto_data **pd_p;
        unsigned int hash = IP_VS_PROTO_HASH(pd->pp->protocol);

        pd_p = &ipvs->proto_data_table[hash];
        for (; *pd_p; pd_p = &(*pd_p)->next) {
                if (*pd_p == pd) {
                        *pd_p = pd->next;
                        if (pd->pp->exit_netns != NULL)
                                pd->pp->exit_netns(ipvs, pd);
                        kfree(pd);
                        return 0;
                }
        }

        return -ESRCH;
}

/*
 *      get ip_vs_protocol object by its proto.
 */
struct ip_vs_protocol * ip_vs_proto_get(unsigned short proto)
{
        struct ip_vs_protocol *pp;
        unsigned int hash = IP_VS_PROTO_HASH(proto);

        for (pp = ip_vs_proto_table[hash]; pp; pp = pp->next) {
                if (pp->protocol == proto)
                        return pp;
        }

        return NULL;
}
EXPORT_SYMBOL(ip_vs_proto_get);

/*
 *      get ip_vs_protocol object data by netns and proto
 */
struct ip_vs_proto_data *
ip_vs_proto_data_get(struct netns_ipvs *ipvs, unsigned short proto)
{
        struct ip_vs_proto_data *pd;
        unsigned int hash = IP_VS_PROTO_HASH(proto);

        for (pd = ipvs->proto_data_table[hash]; pd; pd = pd->next) {
                if (pd->pp->protocol == proto)
                        return pd;
        }

        return NULL;
}
EXPORT_SYMBOL(ip_vs_proto_data_get);

/*
 *      Propagate event for state change to all protocols
 */
void ip_vs_protocol_timeout_change(struct netns_ipvs *ipvs, int flags)
{
        struct ip_vs_proto_data *pd;
        int i;

        for (i = 0; i < IP_VS_PROTO_TAB_SIZE; i++) {
                for (pd = ipvs->proto_data_table[i]; pd; pd = pd->next) {
                        if (pd->pp->timeout_change)
                                pd->pp->timeout_change(pd, flags);
                }
        }
}


int *
ip_vs_create_timeout_table(int *table, int size)
{
        return kmemdup(table, size, GFP_KERNEL);
}


const char *ip_vs_state_name(const struct ip_vs_conn *cp)
{
        unsigned int state = cp->state;
        struct ip_vs_protocol *pp;

        if (cp->flags & IP_VS_CONN_F_TEMPLATE) {

                if (state >= IP_VS_CTPL_S_LAST)
                        return "ERR!";
                return ip_vs_ctpl_state_name_table[state] ? : "?";
        }
        pp = ip_vs_proto_get(cp->protocol);
        if (pp == NULL || pp->state_name == NULL)
                return (cp->protocol == IPPROTO_IP) ? "NONE" : "ERR!";
        return pp->state_name(state);
}


static void
ip_vs_tcpudp_debug_packet_v4(struct ip_vs_protocol *pp,
                             const struct sk_buff *skb,
                             int offset,
                             const char *msg)
{
        char buf[128];
        struct iphdr _iph, *ih;

        ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
        if (ih == NULL)
                sprintf(buf, "TRUNCATED");
        else if (ih->frag_off & htons(IP_OFFSET))
                sprintf(buf, "%pI4->%pI4 frag", &ih->saddr, &ih->daddr);
        else {
                __be16 _ports[2], *pptr;

                pptr = skb_header_pointer(skb, offset + ih->ihl*4,
                                          sizeof(_ports), _ports);
                if (pptr == NULL)
                        sprintf(buf, "TRUNCATED %pI4->%pI4",
                                &ih->saddr, &ih->daddr);
                else
                        sprintf(buf, "%pI4:%u->%pI4:%u",
                                &ih->saddr, ntohs(pptr[0]),
                                &ih->daddr, ntohs(pptr[1]));
        }

        pr_debug("%s: %s %s\n", msg, pp->name, buf);
}

#ifdef CONFIG_IP_VS_IPV6
static void
ip_vs_tcpudp_debug_packet_v6(struct ip_vs_protocol *pp,
                             const struct sk_buff *skb,
                             int offset,
                             const char *msg)
{
        char buf[192];
        struct ipv6hdr _iph, *ih;

        ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
        if (ih == NULL)
                sprintf(buf, "TRUNCATED");
        else if (ih->nexthdr == IPPROTO_FRAGMENT)
                sprintf(buf, "%pI6c->%pI6c frag", &ih->saddr, &ih->daddr);
        else {
                __be16 _ports[2], *pptr;

                pptr = skb_header_pointer(skb, offset + sizeof(struct ipv6hdr),
                                          sizeof(_ports), _ports);
                if (pptr == NULL)
                        sprintf(buf, "TRUNCATED %pI6c->%pI6c",
                                &ih->saddr, &ih->daddr);
                else
                        sprintf(buf, "%pI6c:%u->%pI6c:%u",
                                &ih->saddr, ntohs(pptr[0]),
                                &ih->daddr, ntohs(pptr[1]));
        }

        pr_debug("%s: %s %s\n", msg, pp->name, buf);
}
#endif


void
ip_vs_tcpudp_debug_packet(int af, struct ip_vs_protocol *pp,
                          const struct sk_buff *skb,
                          int offset,
                          const char *msg)
{
#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6)
                ip_vs_tcpudp_debug_packet_v6(pp, skb, offset, msg);
        else
#endif
                ip_vs_tcpudp_debug_packet_v4(pp, skb, offset, msg);
}

/*
 * per network name-space init
 */
int __net_init ip_vs_protocol_net_init(struct netns_ipvs *ipvs)
{
        int i, ret;
        static struct ip_vs_protocol *protos[] = {
#ifdef CONFIG_IP_VS_PROTO_TCP
        &ip_vs_protocol_tcp,
#endif
#ifdef CONFIG_IP_VS_PROTO_UDP
        &ip_vs_protocol_udp,
#endif
#ifdef CONFIG_IP_VS_PROTO_SCTP
        &ip_vs_protocol_sctp,
#endif
#ifdef CONFIG_IP_VS_PROTO_AH
        &ip_vs_protocol_ah,
#endif
#ifdef CONFIG_IP_VS_PROTO_ESP
        &ip_vs_protocol_esp,
#endif
        };

        for (i = 0; i < ARRAY_SIZE(protos); i++) {
                ret = register_ip_vs_proto_netns(ipvs, protos[i]);
                if (ret < 0)
                        goto cleanup;
        }
        return 0;

cleanup:
        ip_vs_protocol_net_cleanup(ipvs);
        return ret;
}

void __net_exit ip_vs_protocol_net_cleanup(struct netns_ipvs *ipvs)
{
        struct ip_vs_proto_data *pd;
        int i;

        /* unregister all the ipvs proto data for this netns */
        for (i = 0; i < IP_VS_PROTO_TAB_SIZE; i++) {
                while ((pd = ipvs->proto_data_table[i]) != NULL)
                        unregister_ip_vs_proto_netns(ipvs, pd);
        }
}

int __init ip_vs_protocol_init(void)
{
        char protocols[64] = { 0 };
#define REGISTER_PROTOCOL(p)                    \
        do {                                    \
                register_ip_vs_protocol(p);     \
                strcat(protocols, ", ");        \
                strcat(protocols, (p)->name);   \
        } while (0)

#ifdef CONFIG_IP_VS_PROTO_TCP
        REGISTER_PROTOCOL(&ip_vs_protocol_tcp);
#endif
#ifdef CONFIG_IP_VS_PROTO_UDP
        REGISTER_PROTOCOL(&ip_vs_protocol_udp);
#endif
#ifdef CONFIG_IP_VS_PROTO_SCTP
        REGISTER_PROTOCOL(&ip_vs_protocol_sctp);
#endif
#ifdef CONFIG_IP_VS_PROTO_AH
        REGISTER_PROTOCOL(&ip_vs_protocol_ah);
#endif
#ifdef CONFIG_IP_VS_PROTO_ESP
        REGISTER_PROTOCOL(&ip_vs_protocol_esp);
#endif
        pr_info("Registered protocols (%s)\n", &protocols[2]);

        return 0;
}


void ip_vs_protocol_cleanup(void)
{
        struct ip_vs_protocol *pp;
        int i;

        /* unregister all the ipvs protocols */
        for (i = 0; i < IP_VS_PROTO_TAB_SIZE; i++) {
                while ((pp = ip_vs_proto_table[i]) != NULL)
                        unregister_ip_vs_protocol(pp);
        }
}