From: Yann Bordenave <m...@meowstars.org>

Disambiguation : icmp_error is renamed into icmp_send_error, since it
doesn't manage errors, but only sends ICMP Error messages.

Adding icmp6_send_error to send ICMPv6 Error messages. This function is
simpler than the v4 version.
Adding some calls in various functions to send ICMP errors, when a
received packet is too big, or when its hop limit is 0.

Signed-off-by: Yann Bordenave <m...@meowstars.org>
Signed-off-by: Samuel Thibault <samuel.thiba...@ens-lyon.org>
Reviewed-by: Thomas Huth <th...@redhat.com>
---
 slirp/ip6_icmp.c  | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 slirp/ip6_icmp.h  | 10 +++++++++
 slirp/ip6_input.c | 13 ++++++-----
 slirp/ip_icmp.c   | 12 +++++------
 slirp/ip_icmp.h   |  4 ++--
 slirp/ip_input.c  |  8 +++----
 slirp/socket.c    |  4 ++--
 slirp/tcp_input.c |  2 +-
 slirp/udp.c       |  3 ++-
 9 files changed, 99 insertions(+), 21 deletions(-)

diff --git a/slirp/ip6_icmp.c b/slirp/ip6_icmp.c
index 029d297..1cc65db 100644
--- a/slirp/ip6_icmp.c
+++ b/slirp/ip6_icmp.c
@@ -59,6 +59,70 @@ 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)
+{
+    Slirp *slirp = m->slirp;
+    struct mbuf *t;
+    struct ip6 *ip = mtod(m, struct ip6 *);
+
+    char addrstr[INET6_ADDRSTRLEN];
+    DEBUG_CALL("icmp_send_error");
+    DEBUG_ARGS((dfd, " type = %d, code = %d\n", type, code));
+
+    if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) ||
+            IN6_IS_ADDR_UNSPECIFIED(&ip->ip_src)) {
+        /* TODO icmp error? */
+        return;
+    }
+
+    t = m_get(slirp);
+
+    /* IPv6 packet */
+    struct ip6 *rip = mtod(t, struct ip6 *);
+    rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
+    rip->ip_dst = ip->ip_src;
+    inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN);
+    DEBUG_ARG("target = %s", addrstr);
+
+    rip->ip_nh = IPPROTO_ICMPV6;
+    const int error_data_len = min(m->m_len,
+            IF_MTU - (sizeof(struct ip6) + ICMP6_ERROR_MINLEN));
+    rip->ip_pl = htons(ICMP6_ERROR_MINLEN + error_data_len);
+    t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
+
+    /* ICMPv6 packet */
+    t->m_data += sizeof(struct ip6);
+    struct icmp6 *ricmp = mtod(t, struct icmp6 *);
+    ricmp->icmp6_type = type;
+    ricmp->icmp6_code = code;
+    ricmp->icmp6_cksum = 0;
+
+    switch (type) {
+    case ICMP6_UNREACH:
+    case ICMP6_TIMXCEED:
+        ricmp->icmp6_err.unused = 0;
+        break;
+    case ICMP6_TOOBIG:
+        ricmp->icmp6_err.mtu = htonl(IF_MTU);
+        break;
+    case ICMP6_PARAMPROB:
+        /* TODO: Handle this case */
+        break;
+    default:
+        g_assert_not_reached();
+        break;
+    }
+    t->m_data += ICMP6_ERROR_MINLEN;
+    memcpy(t->m_data, m->m_data, error_data_len);
+
+    /* Checksum */
+    t->m_data -= ICMP6_ERROR_MINLEN;
+    t->m_data -= sizeof(struct ip6);
+    ricmp->icmp6_cksum = ip6_cksum(t);
+
+    ip6_output(NULL, t, 0);
+}
+
 /*
  * Send NDP Router Advertisement
  */
diff --git a/slirp/ip6_icmp.h b/slirp/ip6_icmp.h
index b2c40d6..9460bf8 100644
--- a/slirp/ip6_icmp.h
+++ b/slirp/ip6_icmp.h
@@ -19,6 +19,12 @@ struct icmp6_echo { /* Echo Messages */
     uint16_t seq_num;
 };
 
+union icmp6_error_body {
+    uint32_t unused;
+    uint32_t pointer;
+    uint32_t mtu;
+};
+
 /*
  * NDP Messages
  */
@@ -82,6 +88,7 @@ struct icmp6 {
     uint8_t     icmp6_code;         /* type sub code */
     uint16_t    icmp6_cksum;        /* ones complement cksum of struct */
     union {
+        union icmp6_error_body error_body;
         struct icmp6_echo echo;
         struct ndp_rs ndp_rs;
         struct ndp_ra ndp_ra;
@@ -89,6 +96,7 @@ struct icmp6 {
         struct ndp_na ndp_na;
         struct ndp_redirect ndp_redirect;
     } icmp6_body;
+#define icmp6_err icmp6_body.error_body
 #define icmp6_echo icmp6_body.echo
 #define icmp6_nrs icmp6_body.ndp_rs
 #define icmp6_nra icmp6_body.ndp_ra
@@ -98,6 +106,7 @@ struct icmp6 {
 } QEMU_PACKED;
 
 #define ICMP6_MINLEN    4
+#define ICMP6_ERROR_MINLEN  8
 #define ICMP6_ECHO_MINLEN   8
 #define ICMP6_NDP_RS_MINLEN 8
 #define ICMP6_NDP_RA_MINLEN 16
@@ -197,6 +206,7 @@ struct ndpopt {
 void icmp6_init(Slirp *slirp);
 void icmp6_cleanup(Slirp *slirp);
 void icmp6_input(struct mbuf *);
+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/slirp/ip6_input.c b/slirp/ip6_input.c
index df249f1..b6a438d 100644
--- a/slirp/ip6_input.c
+++ b/slirp/ip6_input.c
@@ -39,9 +39,14 @@ void ip6_input(struct mbuf *m)
         goto bad;
     }
 
+    if (ntohs(ip6->ip_pl) > IF_MTU) {
+        icmp6_send_error(m, ICMP6_TOOBIG, 0);
+        goto bad;
+    }
+
     /* check ip_ttl for a correct ICMP reply */
     if (ip6->ip_hl == 0) {
-        /*icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");*/
+        icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);
         goto bad;
     }
 
@@ -49,14 +54,12 @@ void ip6_input(struct mbuf *m)
      * Switch out to protocol's input routine.
      */
     switch (ip6->ip_nh) {
-#if 0
     case IPPROTO_TCP:
-        tcp_input(m, hlen, (struct socket *)NULL);
+        icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
         break;
     case IPPROTO_UDP:
-        udp_input(m, hlen);
+        icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
         break;
-#endif
     case IPPROTO_ICMPV6:
         icmp6_input(m);
         break;
diff --git a/slirp/ip_icmp.c b/slirp/ip_icmp.c
index ace3982..590dada 100644
--- a/slirp/ip_icmp.c
+++ b/slirp/ip_icmp.c
@@ -38,7 +38,7 @@
 /* Be nice and tell them it's just a pseudo-ping packet */
 static const char icmp_ping_msg[] = "This is a pseudo-PING packet used by 
Slirp to emulate ICMP ECHO-REQUEST packets.\n";
 
-/* list of actions for icmp_error() on RX of an icmp message */
+/* list of actions for icmp_send_error() on RX of an icmp message */
 static const int icmp_flush[19] = {
 /*  ECHO REPLY (0)  */   0,
                         1,
@@ -101,7 +101,7 @@ static int icmp_send(struct socket *so, struct mbuf *m, int 
hlen)
                (struct sockaddr *)&addr, sizeof(addr)) == -1) {
         DEBUG_MISC((dfd, "icmp_input icmp sendto tx errno = %d-%s\n",
                     errno, strerror(errno)));
-        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
+        icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
         icmp_detach(so);
     }
 
@@ -189,7 +189,7 @@ icmp_input(struct mbuf *m, int hlen)
                (struct sockaddr *)&addr, sizeof(addr)) == -1) {
        DEBUG_MISC((dfd,"icmp_input udp sendto tx errno = %d-%s\n",
                    errno,strerror(errno)));
-       icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
+       icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0, strerror(errno));
        udp_detach(so);
       }
     } /* if ip->ip_dst.s_addr == alias_addr.s_addr */
@@ -235,7 +235,7 @@ end_error:
 
 #define ICMP_MAXDATALEN (IP_MSS-28)
 void
-icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
+icmp_send_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
            const char *message)
 {
   unsigned hlen, shlen, s_ip_len;
@@ -243,7 +243,7 @@ icmp_error(struct mbuf *msrc, u_char type, u_char code, int 
minsize,
   register struct icmp *icp;
   register struct mbuf *m;
 
-  DEBUG_CALL("icmp_error");
+  DEBUG_CALL("icmp_send_error");
   DEBUG_ARG("msrc = %p", msrc);
   DEBUG_ARG("msrc_len = %d", msrc->m_len);
 
@@ -433,7 +433,7 @@ void icmp_receive(struct socket *so)
         }
         DEBUG_MISC((dfd, " udp icmp rx errno = %d-%s\n", errno,
                     strerror(errno)));
-        icmp_error(so->so_m, ICMP_UNREACH, error_code, 0, strerror(errno));
+        icmp_send_error(so->so_m, ICMP_UNREACH, error_code, 0, 
strerror(errno));
     } else {
         icmp_reflect(so->so_m);
         so->so_m = NULL; /* Don't m_free() it again! */
diff --git a/slirp/ip_icmp.h b/slirp/ip_icmp.h
index be4426b..846761d 100644
--- a/slirp/ip_icmp.h
+++ b/slirp/ip_icmp.h
@@ -156,8 +156,8 @@ struct icmp {
 void icmp_init(Slirp *slirp);
 void icmp_cleanup(Slirp *slirp);
 void icmp_input(struct mbuf *, int);
-void icmp_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
-                const char *message);
+void icmp_send_error(struct mbuf *msrc, u_char type, u_char code, int minsize,
+                     const char *message);
 void icmp_reflect(struct mbuf *);
 void icmp_receive(struct socket *so);
 void icmp_detach(struct socket *so);
diff --git a/slirp/ip_input.c b/slirp/ip_input.c
index e4855ae..16fb2cb 100644
--- a/slirp/ip_input.c
+++ b/slirp/ip_input.c
@@ -132,9 +132,9 @@ ip_input(struct mbuf *m)
           m_adj(m, ip->ip_len - m->m_len);
 
        /* check ip_ttl for a correct ICMP reply */
-       if(ip->ip_ttl==0) {
-         icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
-         goto bad;
+       if (ip->ip_ttl == 0) {
+           icmp_send_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, "ttl");
+           goto bad;
        }
 
        /*
@@ -637,7 +637,7 @@ typedef uint32_t n_time;
        }
        return (0);
 bad:
-       icmp_error(m, type, code, 0, 0);
+       icmp_send_error(m, type, code, 0, 0);
 
        return (1);
 }
diff --git a/slirp/socket.c b/slirp/socket.c
index 2b5453e..32b1ba3 100644
--- a/slirp/socket.c
+++ b/slirp/socket.c
@@ -463,7 +463,7 @@ sorecvfrom(struct socket *so)
 
            DEBUG_MISC((dfd," udp icmp rx errno = %d-%s\n",
                        errno,strerror(errno)));
-           icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+           icmp_send_error(so->so_m, ICMP_UNREACH, code, 0, strerror(errno));
          } else {
            icmp_reflect(so->so_m);
             so->so_m = NULL; /* Don't m_free() it again! */
@@ -511,7 +511,7 @@ sorecvfrom(struct socket *so)
            else if(errno == ENETUNREACH) code=ICMP_UNREACH_NET;
 
            DEBUG_MISC((dfd," rx error, tx icmp ICMP_UNREACH:%i\n", code));
-           icmp_error(so->so_m, ICMP_UNREACH,code, 0,strerror(errno));
+           icmp_send_error(so->so_m, ICMP_UNREACH, code, 0, strerror(errno));
            m_free(m);
          } else {
          /*
diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
index 2027a75..5f845da 100644
--- a/slirp/tcp_input.c
+++ b/slirp/tcp_input.c
@@ -608,7 +608,7 @@ findso:
              m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
              m->m_len  += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
              *ip=save_ip;
-             icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));
+             icmp_send_error(m, ICMP_UNREACH, code, 0, strerror(errno));
            }
             tcp_close(tp);
            m_free(m);
diff --git a/slirp/udp.c b/slirp/udp.c
index 6b39cab..be012fb 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -209,7 +209,8 @@ udp_input(register struct mbuf *m, int iphlen)
          m->m_data -= iphlen;
          *ip=save_ip;
          DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
-         icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
+         icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0,
+                         strerror(errno));
          goto bad;
        }
 
-- 
2.7.0


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