ip_vs_proto.c

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/*
 * ip_vs_proto.c: transport protocol load balancing support for IPVS
 *
 * Authors:     Wensong Zhang <[email protected]>
 *              Julian Anastasov <[email protected]>
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Changes:
 *
 */

#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " 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];


/*
 *  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 net *net, struct ip_vs_protocol *pp)
{
    struct netns_ipvs *ipvs = net_ipvs(net);
    unsigned int hash = IP_VS_PROTO_HASH(pp->protocol);
    struct ip_vs_proto_data *pd =
            kzalloc(sizeof(struct ip_vs_proto_data), GFP_KERNEL);

    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(net, 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 net *net, struct ip_vs_proto_data *pd)
{
    struct netns_ipvs *ipvs = net_ipvs(net);
    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(net, 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
 */
static struct ip_vs_proto_data *
__ipvs_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;
}

struct ip_vs_proto_data *
ip_vs_proto_data_get(struct net *net, unsigned short proto)
{
    struct netns_ipvs *ipvs = net_ipvs(net);

    return __ipvs_proto_data_get(ipvs, proto);
}
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);
}


/*
 *  Set timeout value for state specified by name
 */
int
ip_vs_set_state_timeout(int *table, int num, const char *const *names,
            const char *name, int to)
{
    int i;

    if (!table || !name || !to)
        return -EINVAL;

    for (i = 0; i < num; i++) {
        if (strcmp(names[i], name))
            continue;
        table[i] = to * HZ;
        return 0;
    }
    return -ENOENT;
}


const char * ip_vs_state_name(__u16 proto, int state)
{
    struct ip_vs_protocol *pp = ip_vs_proto_get(proto);

    if (pp == NULL || pp->state_name == NULL)
        return (IPPROTO_IP == proto) ? "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, "%pI6->%pI6 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 %pI6->%pI6",
                &ih->saddr, &ih->daddr);
        else
            sprintf(buf, "%pI6:%u->%pI6:%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 net *net)
{
    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(net, protos[i]);
        if (ret < 0)
            goto cleanup;
    }
    return 0;

cleanup:
    ip_vs_protocol_net_cleanup(net);
    return ret;
}

void __net_exit ip_vs_protocol_net_cleanup(struct net *net)
{
    struct netns_ipvs *ipvs = net_ipvs(net);
    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(net, pd);
    }
}

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

    protocols[0] = '\0';
    protocols[2] = '\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);
    }
}