Merge branch 'errors' into 'master'

Enable forwarding ICMP errors

See merge request slirp/libslirp!49

6 files changed, 96 insertions, 6 deletions

diff --git a/src/ip6_icmp.c b/src/ip6_icmp.c
index d9c872b..119c8be 100644
--- a/src/ip6_icmp.c
+++ b/src/ip6_icmp.c
@@ -69,7 +69,7 @@ static void icmp6_send_echoreply(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
     ip6_output(NULL, t, 0);
 }
 
-void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
+void icmp6_forward_error(struct mbuf *m, uint8_t type, uint8_t code, struct in6_addr *src)
 {
     Slirp *slirp = m->slirp;
     struct mbuf *t;
@@ -88,7 +88,7 @@ void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
 
     /* IPv6 packet */
     struct ip6 *rip = mtod(t, struct ip6 *);
-    rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
+    rip->ip_src = *src;
     rip->ip_dst = ip->ip_src;
     inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN);
     DEBUG_ARG("target = %s", addrstr);
@@ -131,6 +131,12 @@ void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
     ip6_output(NULL, t, 0);
 }
 
+void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
+{
+    struct in6_addr src = LINKLOCAL_ADDR;
+    icmp6_forward_error(m, type, code, &src);
+}
+
 /*
  * Send NDP Router Advertisement
  */
diff --git a/src/ip6_icmp.h b/src/ip6_icmp.h
index c37e60f..9070999 100644
--- a/src/ip6_icmp.h
+++ b/src/ip6_icmp.h
@@ -212,6 +212,7 @@ struct ndpopt {
 void icmp6_init(Slirp *slirp);
 void icmp6_cleanup(Slirp *slirp);
 void icmp6_input(struct mbuf *);
+void icmp6_forward_error(struct mbuf *m, uint8_t type, uint8_t code, struct in6_addr *src);
 void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code);
 void ndp_send_ra(Slirp *slirp);
 void ndp_send_ns(Slirp *slirp, struct in6_addr addr);
diff --git a/src/ip_icmp.c b/src/ip_icmp.c
index 45694cd..f4d686b 100644
--- a/src/ip_icmp.c
+++ b/src/ip_icmp.c
@@ -271,8 +271,8 @@ end_error:
  */
 
 #define ICMP_MAXDATALEN (IP_MSS - 28)
-void icmp_send_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
-                     const char *message)
+void icmp_forward_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
+                        const char *message, struct in_addr *src)
 {
     unsigned hlen, shlen, s_ip_len;
     register struct ip *ip;
@@ -387,7 +387,7 @@ void icmp_send_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
     ip->ip_ttl = MAXTTL;
     ip->ip_p = IPPROTO_ICMP;
     ip->ip_dst = ip->ip_src; /* ip addresses */
-    ip->ip_src = m->slirp->vhost_addr;
+    ip->ip_src = *src;
 
     (void)ip_output((struct socket *)NULL, m);
 
@@ -396,6 +396,12 @@ end_error:
 }
 #undef ICMP_MAXDATALEN
 
+void icmp_send_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
+                     const char *message)
+{
+    icmp_forward_error(msrc, type, code, minsize, message, &msrc->slirp->vhost_addr);
+}
+
 /*
  * Reflect the ip packet back to the source
  */
diff --git a/src/ip_icmp.h b/src/ip_icmp.h
index 84707db..569a083 100644
--- a/src/ip_icmp.h
+++ b/src/ip_icmp.h
@@ -157,6 +157,8 @@ struct icmp {
 void icmp_init(Slirp *slirp);
 void icmp_cleanup(Slirp *slirp);
 void icmp_input(struct mbuf *, int);
+void icmp_forward_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
+                        const char *message, struct in_addr *src);
 void icmp_send_error(struct mbuf *msrc, uint8_t type, uint8_t code, int minsize,
                      const char *message);
 void icmp_reflect(struct mbuf *);
diff --git a/src/socket.c b/src/socket.c
index 3fbb873..0d9b8e3 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -8,6 +8,9 @@
 #ifdef __sun__
 #include <sys/filio.h>
 #endif
+#ifdef __linux__
+#include <linux/errqueue.h>
+#endif
 
 static void sofcantrcvmore(struct socket *so);
 static void sofcantsendmore(struct socket *so);
@@ -494,12 +497,67 @@ void sorecvfrom(struct socket *so)
     struct sockaddr_storage addr;
     struct sockaddr_storage saddr, daddr;
     socklen_t addrlen = sizeof(struct sockaddr_storage);
+    char buff[256];
+
+#ifdef __linux__
+    ssize_t size;
+    struct msghdr msg;
+    struct iovec iov;
+    char control[1024];
+
+    /* First look for errors */
+    memset(&msg, 0, sizeof(msg));
+    msg.msg_name = &saddr;
+    msg.msg_namelen = sizeof(saddr);
+    msg.msg_control = control;
+    msg.msg_controllen = sizeof(control);
+    iov.iov_base = buff;
+    iov.iov_len = sizeof(buff);
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+
+    size = recvmsg(so->s, &msg, MSG_ERRQUEUE);
+    if (size >= 0) {
+        struct cmsghdr *cmsg;
+        for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+
+            if (cmsg->cmsg_level == IPPROTO_IP &&
+                cmsg->cmsg_type == IP_RECVERR) {
+                struct sock_extended_err *ee =
+                    (struct sock_extended_err *) CMSG_DATA(cmsg);
+
+                if (ee->ee_origin == SO_EE_ORIGIN_ICMP) {
+                    /* Got an ICMP error, forward it */
+                    struct sockaddr_in *sin;
+
+                    sin = (struct sockaddr_in *) SO_EE_OFFENDER(ee);
+                    icmp_forward_error(so->so_m, ee->ee_type, ee->ee_code,
+                                       0, NULL, &sin->sin_addr);
+                }
+            }
+            else if (cmsg->cmsg_level == IPPROTO_IPV6 &&
+                     cmsg->cmsg_type == IPV6_RECVERR) {
+                struct sock_extended_err *ee =
+                    (struct sock_extended_err *) CMSG_DATA(cmsg);
+
+                if (ee->ee_origin == SO_EE_ORIGIN_ICMP6) {
+                    /* Got an ICMPv6 error, forward it */
+                    struct sockaddr_in6 *sin6;
+
+                    sin6 = (struct sockaddr_in6 *) SO_EE_OFFENDER(ee);
+                    icmp6_forward_error(so->so_m, ee->ee_type, ee->ee_code,
+                                        &sin6->sin6_addr);
+                }
+            }
+        }
+        return;
+    }
+#endif
 
     DEBUG_CALL("sorecvfrom");
     DEBUG_ARG("so = %p", so);
 
     if (so->so_type == IPPROTO_ICMP) { /* This is a "ping" reply */
-        char buff[256];
         int len;
 
         len = recvfrom(so->s, buff, 256, 0, (struct sockaddr *)&addr, &addrlen);
diff --git a/src/udp.c b/src/udp.c
index b5b4210..050cee4 100644
--- a/src/udp.c
+++ b/src/udp.c
@@ -303,6 +303,23 @@ int udp_attach(struct socket *so, unsigned short af)
             so->s = -1;
             return -1;
         }
+
+#ifdef __linux__
+        {
+            int opt = 1;
+            switch (af) {
+            case AF_INET:
+                setsockopt(so->s, IPPROTO_IP, IP_RECVERR, &opt, sizeof(opt));
+                break;
+            case AF_INET6:
+                setsockopt(so->s, IPPROTO_IPV6, IPV6_RECVERR, &opt, sizeof(opt));
+                break;
+            default:
+                g_assert_not_reached();
+            }
+        }
+#endif
+
         so->so_expire = curtime + SO_EXPIRE;
         insque(so, &so->slirp->udb);
     }