X-Git-Url: https://git.distorted.org.uk/~mdw/secnet/blobdiff_plain/091433c62a7e2fdb12f60d2468c5f98b9603f429..826b47e921488742fd77f31352fa04df3a5d0e11:/netlink.c

diff --git a/netlink.c b/netlink.c
index 954dbb6..50a920f 100644
--- a/netlink.c
+++ b/netlink.c
@@ -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);
 	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);
     }
 }