site: Permit multiple peer addresses even if peer is static

[secnet.git] / netlink.c

diff --git a/netlink.c b/netlink.c
index 954dbb66f6385e8b65fcd0e9948d521442f0a4cd..e197e80f8c69508f5f617d9af86b1bfa07957098 100644 (file)
--- a/netlink.c
+++ b/netlink.c
@@ -180,7 +180,7 @@ static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl) {
     return sum;
 }
 #else
-static inline uint16_t ip_fast_csum(uint8_t *iph, int32_t ihl)
+static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl)
 {
     assert(ihl < INT_MAX/4);
     return ip_csum(iph,ihl*4);
@@ -237,6 +237,15 @@ struct icmphdr {
 
 static const union icmpinfofield icmp_noinfo;
     
+static void netlink_client_deliver(struct netlink *st,
+                                  struct netlink_client *client,
+                                  uint32_t source, uint32_t dest,
+                                  struct buffer_if *buf);
+static void netlink_host_deliver(struct netlink *st,
+                                struct netlink_client *sender,
+                                uint32_t source, uint32_t dest,
+                                struct buffer_if *buf);
+
 static const char *sender_name(struct netlink_client *sender /* or NULL */)
 {
     return sender?sender->name:"(local)";
@@ -254,7 +263,8 @@ static void netlink_packet_deliver(struct netlink *st,
    settable.
    */
 static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
-                                        uint32_t dest,uint16_t len)
+                                        uint32_t source, uint32_t dest,
+                                        uint16_t len)
 {
     struct icmphdr *h;
 
@@ -270,7 +280,7 @@ static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
     h->iph.frag=0;
     h->iph.ttl=255; /* XXX should be configurable */
     h->iph.protocol=1;
-    h->iph.saddr=htonl(st->secnet_address);
+    h->iph.saddr=htonl(source);
     h->iph.daddr=htonl(dest);
     h->iph.check=0;
     h->iph.check=ip_fast_csum((uint8_t *)&h->iph,h->iph.ihl);
@@ -392,12 +402,44 @@ static void netlink_icmp_simple(struct netlink *st,
 
     if (netlink_icmp_may_reply(buf)) {
        struct iphdr *iph=(struct iphdr *)buf->start;
+
+       uint32_t icmpdest = ntohl(iph->saddr);
+       uint32_t icmpsource;
+       const char *icmpsourcedebugprefix;
+       if (!st->ptp) {
+           icmpsource=st->secnet_address;
+           icmpsourcedebugprefix="";
+       } else if (origsender) {
+           /* was from peer, send reply as if from host */
+           icmpsource=st->local_address;
+           icmpsourcedebugprefix="L!";
+       } else {
+           /* was from host, send reply as if from peer */
+           icmpsource=st->secnet_address; /* actually, peer address */
+           icmpsourcedebugprefix="P!";
+       }
+       MDEBUG("%s: generating ICMP re %s[%s]->[%s]:"
+              " from %s%s type=%u code=%u\n",
+              st->name, sender_name(origsender),
+              ipaddr_to_string(ntohl(iph->saddr)),
+              ipaddr_to_string(ntohl(iph->daddr)),
+              icmpsourcedebugprefix,
+              ipaddr_to_string(icmpsource),
+              type, code);
+
        len=netlink_icmp_reply_len(buf);
-       h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
+       h=netlink_icmp_tmpl(st,icmpsource,icmpdest,len);
        h->type=type; h->code=code; h->d=info;
-       memcpy(buf_append(&st->icmp,len),buf->start,len);
+       BUF_ADD_BYTES(append,&st->icmp,buf->start,len);
        netlink_icmp_csum(h);
-       netlink_packet_deliver(st,NULL,&st->icmp);
+
+       if (!st->ptp) {
+           netlink_packet_deliver(st,NULL,&st->icmp);
+       } else if (origsender) {
+           netlink_client_deliver(st,origsender,icmpsource,icmpdest,&st->icmp);
+       } else {
+           netlink_host_deliver(st,NULL,icmpsource,icmpdest,&st->icmp);
+       }
        BUF_ASSERT_FREE(&st->icmp);
     }
 }
@@ -549,7 +591,7 @@ static void netlink_maybe_fragment(struct netlink *st,
        long avail = mtu - hl;
        long remain = endindata - indata;
        long use = avail < remain ? (avail & ~(long)7) : remain;
-       memcpy(buf_append(buf, use), indata, use);
+       BUF_ADD_BYTES(append, buf, indata, use);
        indata += use;
 
        _Bool last_frag = indata >= endindata;
@@ -595,7 +637,6 @@ static void netlink_client_deliver(struct netlink *st,
        d=ipaddr_to_string(dest);
        Message(M_ERR,"%s: dropping %s->%s, client not registered\n",
                st->name,s,d);
-       free(s); free(d);
        BUF_FREE(buf);
        return;
     }
@@ -702,7 +743,6 @@ static void netlink_packet_deliver(struct netlink *st,
            d=ipaddr_to_string(dest);
            Message(M_DEBUG,"%s: don't know where to deliver packet "
                    "(s=%s, d=%s)\n", st->name, s, d);
-           free(s); free(d);
            netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
                                ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
            BUF_FREE(buf);
@@ -718,7 +758,6 @@ static void netlink_packet_deliver(struct netlink *st,
               with destination network administratively prohibited */
            Message(M_NOTICE,"%s: denied forwarding for packet (s=%s, d=%s)\n",
                    st->name,s,d);
-           free(s); free(d);
                    
            netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
                                ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
@@ -857,7 +896,6 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *sender,
            d=ipaddr_to_string(dest);
            Message(M_WARNING,"%s: packet from tunnel %s with bad "
                    "source address (s=%s,d=%s)\n",st->name,sender->name,s,d);
-           free(s); free(d);
            BUF_FREE(buf);
            return;
        }
@@ -871,7 +909,6 @@ static void netlink_incoming(struct netlink *st, struct netlink_client *sender,
            d=ipaddr_to_string(dest);
            Message(M_WARNING,"%s: outgoing packet with bad source address "
                    "(s=%s,d=%s)\n",st->name,s,d);
-           free(s); free(d);
            BUF_FREE(buf);
            return;
        }
@@ -939,7 +976,6 @@ static void netlink_output_subnets(struct netlink *st, uint32_t loglevel,
     for (i=0; i<snets->entries; i++) {
        net=subnet_to_string(snets->list[i]);
        Message(loglevel,"%s ",net);
-       free(net);
     }
 }
 
@@ -954,7 +990,6 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
        net=ipaddr_to_string(st->secnet_address);
        Message(c,"%s: point-to-point (remote end is %s); routes: ",
                st->name, net);
-       free(net);
        netlink_output_subnets(st,c,st->clients->subnets);
        Message(c,"\n");
     } else {
@@ -975,11 +1010,9 @@ static void netlink_dump_routes(struct netlink *st, bool_t requested)
        net=ipaddr_to_string(st->secnet_address);
        Message(c,"%s/32 -> netlink \"%s\" (use %d)\n",
                net,st->name,st->localcount);
-       free(net);
        for (i=0; i<st->subnets->entries; i++) {
            net=subnet_to_string(st->subnets->list[i]);
            Message(c,"%s ",net);
-           free(net);
        }
        if (i>0)
            Message(c,"-> host (use %d)\n",st->outcount);