Implements TTL security for OSPF and RIP.

Interfaces for OSPF and RIP could be configured to use (and request)
TTL 255 for traffic to direct neighbors.

Thanks to Simon Dickhoven for the original patch for RIPng.

1 files changed, 32 insertions, 12 deletions

diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 434a05be..93863885 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -673,7 +673,7 @@ get_sockaddr(struct sockaddr_in *sa, ip_addr *a, struct iface **ifa, unsigned *p
 #ifdef IPV6
 
 /* PKTINFO handling is also standardized in IPv6 */
-#define CMSG_RX_SPACE CMSG_SPACE(sizeof(struct in6_pktinfo))
+#define CMSG_RX_SPACE (CMSG_SPACE(sizeof(struct in6_pktinfo)) + CMSG_SPACE(sizeof(int)))
 #define CMSG_TX_SPACE CMSG_SPACE(sizeof(struct in6_pktinfo))
 
 /*
@@ -685,15 +685,26 @@ get_sockaddr(struct sockaddr_in *sa, ip_addr *a, struct iface **ifa, unsigned *p
 #ifndef IPV6_RECVPKTINFO
 #define IPV6_RECVPKTINFO IPV6_PKTINFO
 #endif
+/*
+ * Same goes for IPV6_HOPLIMIT -> IPV6_RECVHOPLIMIT.
+ */
+#ifndef IPV6_RECVHOPLIMIT
+#define IPV6_RECVHOPLIMIT IPV6_HOPLIMIT
+#endif
 
 static char *
 sysio_register_cmsgs(sock *s)
 {
   int ok = 1;
+
   if ((s->flags & SKF_LADDR_RX) &&
-      setsockopt(s->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &ok, sizeof(ok)) < 0)
+      (setsockopt(s->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &ok, sizeof(ok)) < 0))
     return "IPV6_RECVPKTINFO";
 
+  if ((s->flags & SKF_TTL_RX) &&
+      (setsockopt(s->fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &ok, sizeof(ok)) < 0))
+    return "IPV6_RECVHOPLIMIT";
+
   return NULL;
 }
 
@@ -702,25 +713,34 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 {
   struct cmsghdr *cm;
   struct in6_pktinfo *pi = NULL;
-
-  if (!(s->flags & SKF_LADDR_RX))
-    return;
+  int *hlim = NULL;
 
   for (cm = CMSG_FIRSTHDR(msg); cm != NULL; cm = CMSG_NXTHDR(msg, cm))
+  {
+    if (cm->cmsg_level == IPPROTO_IPV6 && cm->cmsg_type == IPV6_PKTINFO)
+      pi = (struct in6_pktinfo *) CMSG_DATA(cm);
+
+    if (cm->cmsg_level == IPPROTO_IPV6 && cm->cmsg_type == IPV6_HOPLIMIT)
+      hlim = (int *) CMSG_DATA(cm);
+  }
+
+  if (s->flags & SKF_LADDR_RX)
+  {
+    if (pi)
     {
-      if (cm->cmsg_level == IPPROTO_IPV6 && cm->cmsg_type == IPV6_PKTINFO)
-	pi = (struct in6_pktinfo *) CMSG_DATA(cm);
+      get_inaddr(&s->laddr, &pi->ipi6_addr);
+      s->lifindex = pi->ipi6_ifindex;
     }
-
-  if (!pi)
+    else
     {
       s->laddr = IPA_NONE;
       s->lifindex = 0;
-      return;
     }
+  }
+
+  if (s->flags & SKF_TTL_RX)
+    s->ttl = hlim ? *hlim : -1;
 
-  get_inaddr(&s->laddr, &pi->ipi6_addr);
-  s->lifindex = pi->ipi6_ifindex;
   return;
 }