net/ipv4/ipvs/ip_vs_proto_esp.c

   1 /*
   2  * ip_vs_proto_esp.c:   ESP IPSec load balancing support for IPVS
   3  *
   4  * Authors:     Julian Anastasov <ja@ssi.bg>, February 2002
   5  *              Wensong Zhang <wensong@linuxvirtualserver.org>
   6  *
   7  *              This program is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              version 2 as published by the Free Software Foundation;
  10  *
  11  */
  12
  13 #include <linux/in.h>
  14 #include <linux/ip.h>
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/netfilter_ipv4.h>
  19
  20 #include <net/ip_vs.h>
  21
  22
  23 /* TODO:
  24
  25 struct isakmp_hdr {
  26         __u8            icookie[8];
  27         __u8            rcookie[8];
  28         __u8            np;
  29         __u8            version;
  30         __u8            xchgtype;
  31         __u8            flags;
  32         __u32           msgid;
  33         __u32           length;
  34 };
  35
  36 */
  37
  38 #define PORT_ISAKMP     500
  39
  40
  41 static struct ip_vs_conn *
  42 esp_conn_in_get(const struct sk_buff *skb,
  43                 struct ip_vs_protocol *pp,
  44                 const struct iphdr *iph,
  45                 unsigned int proto_off,
  46                 int inverse)
  47 {
  48         struct ip_vs_conn *cp;
  49
  50         if (likely(!inverse)) {
  51                 cp = ip_vs_conn_in_get(IPPROTO_UDP,
  52                                        iph->saddr,
  53                                        htons(PORT_ISAKMP),
  54                                        iph->daddr,
  55                                        htons(PORT_ISAKMP));
  56         } else {
  57                 cp = ip_vs_conn_in_get(IPPROTO_UDP,
  58                                        iph->daddr,
  59                                        htons(PORT_ISAKMP),
  60                                        iph->saddr,
  61                                        htons(PORT_ISAKMP));
  62         }
  63
  64         if (!cp) {
  65                 /*
  66                  * We are not sure if the packet is from our
  67                  * service, so our conn_schedule hook should return NF_ACCEPT
  68                  */
  69                 IP_VS_DBG(12, "Unknown ISAKMP entry for outin packet "
  70                           "%s%s %u.%u.%u.%u->%u.%u.%u.%u\n",
  71                           inverse ? "ICMP+" : "",
  72                           pp->name,
  73                           NIPQUAD(iph->saddr),
  74                           NIPQUAD(iph->daddr));
  75         }
  76
  77         return cp;
  78 }
  79
  80
  81 static struct ip_vs_conn *
  82 esp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
  83                  const struct iphdr *iph, unsigned int proto_off, int inverse)
  84 {
  85         struct ip_vs_conn *cp;
  86
  87         if (likely(!inverse)) {
  88                 cp = ip_vs_conn_out_get(IPPROTO_UDP,
  89                                         iph->saddr,
  90                                         htons(PORT_ISAKMP),
  91                                         iph->daddr,
  92                                         htons(PORT_ISAKMP));
  93         } else {
  94                 cp = ip_vs_conn_out_get(IPPROTO_UDP,
  95                                         iph->daddr,
  96                                         htons(PORT_ISAKMP),
  97                                         iph->saddr,
  98                                         htons(PORT_ISAKMP));
  99         }
 100
 101         if (!cp) {
 102                 IP_VS_DBG(12, "Unknown ISAKMP entry for inout packet "
 103                           "%s%s %u.%u.%u.%u->%u.%u.%u.%u\n",
 104                           inverse ? "ICMP+" : "",
 105                           pp->name,
 106                           NIPQUAD(iph->saddr),
 107                           NIPQUAD(iph->daddr));
 108         }
 109
 110         return cp;
 111 }
 112
 113
 114 static int
 115 esp_conn_schedule(struct sk_buff *skb, struct ip_vs_protocol *pp,
 116                   int *verdict, struct ip_vs_conn **cpp)
 117 {
 118         /*
 119          * ESP is only related traffic. Pass the packet to IP stack.
 120          */
 121         *verdict = NF_ACCEPT;
 122         return 0;
 123 }
 124
 125
 126 static void
 127 esp_debug_packet(struct ip_vs_protocol *pp, const struct sk_buff *skb,
 128                  int offset, const char *msg)
 129 {
 130         char buf[256];
 131         struct iphdr _iph, *ih;
 132
 133         ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
 134         if (ih == NULL)
 135                 sprintf(buf, "%s TRUNCATED", pp->name);
 136         else
 137                 sprintf(buf, "%s %u.%u.%u.%u->%u.%u.%u.%u",
 138                         pp->name, NIPQUAD(ih->saddr),
 139                         NIPQUAD(ih->daddr));
 140
 141         printk(KERN_DEBUG "IPVS: %s: %s\n", msg, buf);
 142 }
 143
 144
 145 static void esp_init(struct ip_vs_protocol *pp)
 146 {
 147         /* nothing to do now */
 148 }
 149
 150
 151 static void esp_exit(struct ip_vs_protocol *pp)
 152 {
 153         /* nothing to do now */
 154 }
 155
 156
 157 struct ip_vs_protocol ip_vs_protocol_esp = {
 158         .name =                 "ESP",
 159         .protocol =             IPPROTO_ESP,
 160         .num_states =           1,
 161         .dont_defrag =          1,
 162         .init =                 esp_init,
 163         .exit =                 esp_exit,
 164         .conn_schedule =        esp_conn_schedule,
 165         .conn_in_get =          esp_conn_in_get,
 166         .conn_out_get =         esp_conn_out_get,
 167         .snat_handler =         NULL,
 168         .dnat_handler =         NULL,
 169         .csum_check =           NULL,
 170         .state_transition =     NULL,
 171         .register_app =         NULL,
 172         .unregister_app =       NULL,
 173         .app_conn_bind =        NULL,
 174         .debug_packet =         esp_debug_packet,
 175         .timeout_change =       NULL,           /* ISAKMP */
 176 };