Merge branch 'ttl' into 'master'

udp, udp6, icmp: handle TTL value

See merge request slirp/libslirp!48

3 files changed, 45 insertions, 0 deletions

diff --git a/src/ip_icmp.c b/src/ip_icmp.c
index 13a0e55..45694cd 100644
--- a/src/ip_icmp.c
+++ b/src/ip_icmp.c
@@ -176,6 +176,8 @@ void icmp_input(struct mbuf *m, int hlen)
         } else {
             struct socket *so;
             struct sockaddr_storage addr;
+            int ttl;
+
             so = socreate(slirp);
             if (icmp_send(so, m, hlen) == 0) {
                 return;
@@ -207,6 +209,19 @@ void icmp_input(struct mbuf *m, int hlen)
                 return;
             }
 
+            /*
+             * Check for TTL
+             */
+            ttl = ip->ip_ttl-1;
+            if (ttl <= 0) {
+                DEBUG_MISC("udp ttl exceeded");
+                icmp_send_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0,
+                                NULL);
+                udp_detach(so);
+                break;
+            }
+            setsockopt(so->s, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
+
             if (sendto(so->s, icmp_ping_msg, strlen(icmp_ping_msg), 0,
                        (struct sockaddr *)&addr, sockaddr_size(&addr)) == -1) {
                 DEBUG_MISC("icmp_input udp sendto tx errno = %d-%s", errno,
diff --git a/src/udp.c b/src/udp.c
index 0ad44d7..b5b4210 100644
--- a/src/udp.c
+++ b/src/udp.c
@@ -74,6 +74,7 @@ void udp_input(register struct mbuf *m, int iphlen)
     struct socket *so;
     struct sockaddr_storage lhost;
     struct sockaddr_in *lhost4;
+    int ttl;
 
     DEBUG_CALL("udp_input");
     DEBUG_ARG("m = %p", m);
@@ -203,6 +204,20 @@ void udp_input(register struct mbuf *m, int iphlen)
     m->m_data += iphlen;
 
     /*
+     * Check for TTL
+     */
+    ttl = save_ip.ip_ttl-1;
+    if (ttl <= 0) {
+        m->m_len += iphlen;
+        m->m_data -= iphlen;
+        *ip = save_ip;
+        DEBUG_MISC("udp ttl exceeded");
+        icmp_send_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, NULL);
+        goto bad;
+    }
+    setsockopt(so->s, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
+
+    /*
      * Now we sendto() the packet.
      */
     if (sosendto(so, m) == -1) {
diff --git a/src/udp6.c b/src/udp6.c
index 6f9486b..fdd8089 100644
--- a/src/udp6.c
+++ b/src/udp6.c
@@ -17,6 +17,7 @@ void udp6_input(struct mbuf *m)
     int len;
     struct socket *so;
     struct sockaddr_in6 lhost;
+    int hop_limit;
 
     DEBUG_CALL("udp6_input");
     DEBUG_ARG("m = %p", m);
@@ -111,6 +112,20 @@ void udp6_input(struct mbuf *m)
     m->m_data += iphlen;
 
     /*
+     * Check for TTL
+     */
+    hop_limit = save_ip.ip_hl-1;
+    if (hop_limit <= 0) {
+        m->m_len += iphlen;
+        m->m_data -= iphlen;
+        *ip = save_ip;
+        DEBUG_MISC("udp ttl exceeded");
+        icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);
+        goto bad;
+    }
+    setsockopt(so->s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hop_limit, sizeof(hop_limit));
+
+    /*
      * Now we sendto() the packet.
      */
     if (sosendto(so, m) == -1) {