1 files changed, 26 insertions, 12 deletions

diff --git a/sysdep/linux/sysio.h b/sysdep/linux/sysio.h
index 41287e71..250ed586 100644
--- a/sysdep/linux/sysio.h
+++ b/sysdep/linux/sysio.h
@@ -194,17 +194,22 @@ sk_set_md5_auth_int(sock *s, sockaddr *sa, char *passwd)
 /* RX/TX packet info handling for IPv4 */
 /* Mostly similar to standardized IPv6 code */
 
-#define CMSG_RX_SPACE CMSG_SPACE(sizeof(struct in_pktinfo))
+#define CMSG_RX_SPACE (CMSG_SPACE(sizeof(struct in_pktinfo)) + CMSG_SPACE(sizeof(int)))
 #define CMSG_TX_SPACE CMSG_SPACE(sizeof(struct in_pktinfo))
 
 static char *
 sysio_register_cmsgs(sock *s)
 {
   int ok = 1;
+
   if ((s->flags & SKF_LADDR_RX) &&
-      setsockopt(s->fd, IPPROTO_IP, IP_PKTINFO, &ok, sizeof(ok)) < 0)
+      (setsockopt(s->fd, IPPROTO_IP, IP_PKTINFO, &ok, sizeof(ok)) < 0))
     return "IP_PKTINFO";
 
+  if ((s->flags & SKF_TTL_RX) &&
+      (setsockopt(s->fd, IPPROTO_IP, IP_RECVTTL, &ok, sizeof(ok)) < 0))
+    return "IP_RECVTTL";
+
   return NULL;
 }
 
@@ -213,25 +218,34 @@ sysio_process_rx_cmsgs(sock *s, struct msghdr *msg)
 {
   struct cmsghdr *cm;
   struct in_pktinfo *pi = NULL;
-
-  if (!(s->flags & SKF_LADDR_RX))
-    return;
+  int *ttl = NULL;
 
   for (cm = CMSG_FIRSTHDR(msg); cm != NULL; cm = CMSG_NXTHDR(msg, cm))
+  {
+    if (cm->cmsg_level == IPPROTO_IP && cm->cmsg_type == IP_PKTINFO)
+      pi = (struct in_pktinfo *) CMSG_DATA(cm);
+
+    if (cm->cmsg_level == IPPROTO_IP && cm->cmsg_type == IP_TTL)
+      ttl = (int *) CMSG_DATA(cm);
+  }
+
+  if (s->flags & SKF_LADDR_RX)
+  {
+    if (pi)
     {
-      if (cm->cmsg_level == IPPROTO_IP && cm->cmsg_type == IP_PKTINFO)
-	pi = (struct in_pktinfo *) CMSG_DATA(cm);
+      get_inaddr(&s->laddr, &pi->ipi_addr);
+      s->lifindex = pi->ipi_ifindex;
     }
-
-  if (!pi)
+    else
     {
       s->laddr = IPA_NONE;
       s->lifindex = 0;
-      return;
     }
+  }
+
+  if (s->flags & SKF_TTL_RX)
+    s->ttl = ttl ? *ttl : -1;
 
-  get_inaddr(&s->laddr, &pi->ipi_addr);
-  s->lifindex = pi->ipi_ifindex;
   return;
 }