net/ipv4/ipvs/ip_vs_proto_icmp.c

   1 /*
   2  * ip_vs_proto_icmp.c:  ICMP load balancing support for IP Virtual Server
   3  *
   4  * Authors:     Julian Anastasov <ja@ssi.bg>, March 2002
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              version 2 as published by the Free Software Foundation;
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/icmp.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter_ipv4.h>
  17
  18 #include <net/ip_vs.h>
  19
  20
  21 static int icmp_timeouts[1] =           { 1*60*HZ };
  22
  23 static char * icmp_state_name_table[1] = { "ICMP" };
  24
  25 static struct ip_vs_conn *
  26 icmp_conn_in_get(const struct sk_buff *skb,
  27                  struct ip_vs_protocol *pp,
  28                  const struct iphdr *iph,
  29                  unsigned int proto_off,
  30                  int inverse)
  31 {
  32 #if 0
  33         struct ip_vs_conn *cp;
  34
  35         if (likely(!inverse)) {
  36                 cp = ip_vs_conn_in_get(iph->protocol,
  37                         iph->saddr, 0,
  38                         iph->daddr, 0);
  39         } else {
  40                 cp = ip_vs_conn_in_get(iph->protocol,
  41                         iph->daddr, 0,
  42                         iph->saddr, 0);
  43         }
  44
  45         return cp;
  46
  47 #else
  48         return NULL;
  49 #endif
  50 }
  51
  52 static struct ip_vs_conn *
  53 icmp_conn_out_get(const struct sk_buff *skb,
  54                   struct ip_vs_protocol *pp,
  55                   const struct iphdr *iph,
  56                   unsigned int proto_off,
  57                   int inverse)
  58 {
  59 #if 0
  60         struct ip_vs_conn *cp;
  61
  62         if (likely(!inverse)) {
  63                 cp = ip_vs_conn_out_get(iph->protocol,
  64                         iph->saddr, 0,
  65                         iph->daddr, 0);
  66         } else {
  67                 cp = ip_vs_conn_out_get(IPPROTO_UDP,
  68                         iph->daddr, 0,
  69                         iph->saddr, 0);
  70         }
  71
  72         return cp;
  73 #else
  74         return NULL;
  75 #endif
  76 }
  77
  78 static int
  79 icmp_conn_schedule(struct sk_buff *skb, struct ip_vs_protocol *pp,
  80                    int *verdict, struct ip_vs_conn **cpp)
  81 {
  82         *verdict = NF_ACCEPT;
  83         return 0;
  84 }
  85
  86 static int
  87 icmp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
  88 {
  89         if (!(skb->nh.iph->frag_off & __constant_htons(IP_OFFSET))) {
  90                 if (skb->ip_summed != CHECKSUM_UNNECESSARY) {
  91                         if (ip_vs_checksum_complete(skb, skb->nh.iph->ihl * 4)) {
  92                                 IP_VS_DBG_RL_PKT(0, pp, skb, 0, "Failed checksum for");
  93                                 return 0;
  94                         }
  95                 }
  96         }
  97         return 1;
  98 }
  99
 100 static void
 101 icmp_debug_packet(struct ip_vs_protocol *pp,
 102                   const struct sk_buff *skb,
 103                   int offset,
 104                   const char *msg)
 105 {
 106         char buf[256];
 107         struct iphdr _iph, *ih;
 108
 109         ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
 110         if (ih == NULL)
 111                 sprintf(buf, "%s TRUNCATED", pp->name);
 112         else if (ih->frag_off & __constant_htons(IP_OFFSET))
 113                 sprintf(buf, "%s %u.%u.%u.%u->%u.%u.%u.%u frag",
 114                         pp->name, NIPQUAD(ih->saddr),
 115                         NIPQUAD(ih->daddr));
 116         else {
 117                 struct icmphdr _icmph, *ic;
 118
 119                 ic = skb_header_pointer(skb, offset + ih->ihl*4,
 120                                         sizeof(_icmph), &_icmph);
 121                 if (ic == NULL)
 122                         sprintf(buf, "%s TRUNCATED to %u bytes\n",
 123                                 pp->name, skb->len - offset);
 124                 else
 125                         sprintf(buf, "%s %u.%u.%u.%u->%u.%u.%u.%u T:%d C:%d",
 126                                 pp->name, NIPQUAD(ih->saddr),
 127                                 NIPQUAD(ih->daddr),
 128                                 ic->type, ic->code);
 129         }
 130         printk(KERN_DEBUG "IPVS: %s: %s\n", msg, buf);
 131 }
 132
 133 static int
 134 icmp_state_transition(struct ip_vs_conn *cp, int direction,
 135                       const struct sk_buff *skb,
 136                       struct ip_vs_protocol *pp)
 137 {
 138         cp->timeout = pp->timeout_table[IP_VS_ICMP_S_NORMAL];
 139         return 1;
 140 }
 141
 142 static int
 143 icmp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
 144 {
 145         int num;
 146         char **names;
 147
 148         num = IP_VS_ICMP_S_LAST;
 149         names = icmp_state_name_table;
 150         return ip_vs_set_state_timeout(pp->timeout_table, num, names, sname, to);
 151 }
 152
 153
 154 static void icmp_init(struct ip_vs_protocol *pp)
 155 {
 156         pp->timeout_table = icmp_timeouts;
 157 }
 158
 159 static void icmp_exit(struct ip_vs_protocol *pp)
 160 {
 161 }
 162
 163 struct ip_vs_protocol ip_vs_protocol_icmp = {
 164         .name =                 "ICMP",
 165         .protocol =             IPPROTO_ICMP,
 166         .dont_defrag =          0,
 167         .init =                 icmp_init,
 168         .exit =                 icmp_exit,
 169         .conn_schedule =        icmp_conn_schedule,
 170         .conn_in_get =          icmp_conn_in_get,
 171         .conn_out_get =         icmp_conn_out_get,
 172         .snat_handler =         NULL,
 173         .dnat_handler =         NULL,
 174         .csum_check =           icmp_csum_check,
 175         .state_transition =     icmp_state_transition,
 176         .register_app =         NULL,
 177         .unregister_app =       NULL,
 178         .app_conn_bind =        NULL,
 179         .debug_packet =         icmp_debug_packet,
 180         .timeout_change =       NULL,
 181         .set_state_timeout =    icmp_set_state_timeout,
 182 };