slirp: Handle IPv6 in TCP functions

This patch adds IPv6 case in TCP functions refactored by the last
patches.
This also adds IPv6 pseudo-header in tcpiphdr structure.
Finally, tcp_input() is called by ip6_input().

Signed-off-by: Guillaume Subiron <maethor@subiron.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>

6 files changed, 123 insertions, 8 deletions

diff --git a/ip6_input.c b/ip6_input.c
index 9ca6d32..c0b11e7 100644
--- a/ip6_input.c
+++ b/ip6_input.c
@@ -55,7 +55,8 @@ void ip6_input(struct mbuf *m)
      */
     switch (ip6->ip_nh) {
     case IPPROTO_TCP:
-        icmp6_send_error(m, ICMP6_UNREACH, ICMP6_UNREACH_NO_ROUTE);
+        NTOHS(ip6->ip_pl);
+        tcp_input(m, sizeof(struct ip6), (struct socket *)NULL, AF_INET6);
         break;
     case IPPROTO_UDP:
         udp6_input(m);
diff --git a/tcp.h b/tcp.h
index 9007a93..7dbbcd8 100644
--- a/tcp.h
+++ b/tcp.h
@@ -107,6 +107,8 @@ struct tcphdr {
  */
 #undef TCP_MSS
 #define TCP_MSS 1460
+#undef TCP6_MSS
+#define TCP6_MSS 1440
 
 #undef TCP_MAXWIN
 #define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
diff --git a/tcp_input.c b/tcp_input.c
index 7450f7b..99a16ae 100644
--- a/tcp_input.c
+++ b/tcp_input.c
@@ -219,6 +219,7 @@ void tcp_input(struct mbuf *m, int iphlen, struct socket *inso,
                unsigned short af)
 {
     struct ip save_ip, *ip;
+    struct ip6 save_ip6, *ip6;
     register struct tcpiphdr *ti;
     caddr_t optp = NULL;
     int optlen = 0;
@@ -232,6 +233,7 @@ void tcp_input(struct mbuf *m, int iphlen, struct socket *inso,
     int ret;
     struct sockaddr_storage lhost, fhost;
     struct sockaddr_in *lhost4, *fhost4;
+    struct sockaddr_in6 *lhost6, *fhost6;
     struct ex_list *ex_ptr;
     Slirp *slirp;
 
@@ -257,6 +259,9 @@ void tcp_input(struct mbuf *m, int iphlen, struct socket *inso,
     }
     slirp = m->slirp;
 
+    ip = mtod(m, struct ip *);
+    ip6 = mtod(m, struct ip6 *);
+
     switch (af) {
     case AF_INET:
         if (iphlen > sizeof(struct ip)) {
@@ -270,7 +275,6 @@ void tcp_input(struct mbuf *m, int iphlen, struct socket *inso,
          * Save a copy of the IP header in case we want restore it
          * for sending an ICMP error message in response.
          */
-        ip = mtod(m, struct ip *);
         save_ip = *ip;
         save_ip.ip_len += iphlen;
 
@@ -296,16 +300,44 @@ void tcp_input(struct mbuf *m, int iphlen, struct socket *inso,
         ti->ti_dst = save_ip.ip_dst;
         ti->ti_pr = save_ip.ip_p;
         ti->ti_len = htons((uint16_t)tlen);
-        len = ((sizeof(struct tcpiphdr) - sizeof(struct tcphdr)) + tlen);
-        if (cksum(m, len)) {
-            goto drop;
-        }
+        break;
+
+    case AF_INET6:
+        /*
+         * Save a copy of the IP header in case we want restore it
+         * for sending an ICMP error message in response.
+         */
+        save_ip6 = *ip6;
+        /*
+         * Get IP and TCP header together in first mbuf.
+         * Note: IP leaves IP header in first mbuf.
+         */
+        m->m_data -= sizeof(struct tcpiphdr) -
+                     (sizeof(struct ip6) + sizeof(struct tcphdr));
+        m->m_len += sizeof(struct tcpiphdr) -
+                    (sizeof(struct ip6) + sizeof(struct tcphdr));
+        ti = mtod(m, struct tcpiphdr *);
+
+        tlen = ip6->ip_pl;
+        tcpiphdr2qlink(ti)->next = tcpiphdr2qlink(ti)->prev = NULL;
+        memset(&ti->ih_mbuf, 0, sizeof(struct mbuf_ptr));
+        memset(&ti->ti, 0, sizeof(ti->ti));
+        ti->ti_x0 = 0;
+        ti->ti_src6 = save_ip6.ip_src;
+        ti->ti_dst6 = save_ip6.ip_dst;
+        ti->ti_nh6 = save_ip6.ip_nh;
+        ti->ti_len = htons((uint16_t)tlen);
         break;
 
     default:
         g_assert_not_reached();
     }
 
+    len = ((sizeof(struct tcpiphdr) - sizeof(struct tcphdr)) + tlen);
+    if (cksum(m, len)) {
+        goto drop;
+    }
+
     /*
      * Check that TCP offset makes sense,
      * pull out TCP options and adjust length.		XXX
@@ -351,6 +383,14 @@ findso:
         fhost4->sin_addr = ti->ti_dst;
         fhost4->sin_port = ti->ti_dport;
         break;
+    case AF_INET6:
+        lhost6 = (struct sockaddr_in6 *)&lhost;
+        lhost6->sin6_addr = ti->ti_src6;
+        lhost6->sin6_port = ti->ti_sport;
+        fhost6 = (struct sockaddr_in6 *)&fhost;
+        fhost6->sin6_addr = ti->ti_dst6;
+        fhost6->sin6_port = ti->ti_dport;
+        break;
     default:
         g_assert_not_reached();
     }
@@ -409,6 +449,8 @@ findso:
             case AF_INET:
                 so->so_iptos = ((struct ip *)ti)->ip_tos;
                 break;
+            case AF_INET6:
+                break;
             default:
                 g_assert_not_reached();
             }
@@ -631,6 +673,12 @@ findso:
                         code = ICMP_UNREACH_HOST;
                     }
                     break;
+                case AF_INET6:
+                    code = ICMP6_UNREACH_NO_ROUTE;
+                    if (errno == EHOSTUNREACH) {
+                        code = ICMP6_UNREACH_ADDRESS;
+                    }
+                    break;
                 default:
                     g_assert_not_reached();
                 }
@@ -651,6 +699,14 @@ findso:
                     *ip = save_ip;
                     icmp_send_error(m, ICMP_UNREACH, code, 0, strerror(errno));
                     break;
+                case AF_INET6:
+                    m->m_data += sizeof(struct tcpiphdr) -
+                                 (sizeof(struct ip6) + sizeof(struct tcphdr));
+                    m->m_len -= sizeof(struct tcpiphdr) -
+                                (sizeof(struct ip6) + sizeof(struct tcphdr));
+                    *ip6 = save_ip6;
+                    icmp6_send_error(m, ICMP6_UNREACH, code);
+                    break;
                 default:
                     g_assert_not_reached();
                 }
@@ -1511,6 +1567,9 @@ int tcp_mss(struct tcpcb *tp, u_int offer)
     case AF_INET:
         mss = min(IF_MTU, IF_MRU) - sizeof(struct tcphdr) + sizeof(struct ip);
         break;
+    case AF_INET6:
+        mss = min(IF_MTU, IF_MRU) - sizeof(struct tcphdr) + sizeof(struct ip6);
+        break;
     default:
         g_assert_not_reached();
     }
diff --git a/tcp_output.c b/tcp_output.c
index 24b1037..e0061c3 100644
--- a/tcp_output.c
+++ b/tcp_output.c
@@ -62,6 +62,7 @@ int tcp_output(struct tcpcb *tp)
     register struct mbuf *m;
     register struct tcpiphdr *ti, tcpiph_save;
     struct ip *ip;
+    struct ip6 *ip6;
     u_char opt[MAX_TCPOPTLEN];
     unsigned optlen, hdrlen;
     int idle, sendalot;
@@ -464,6 +465,21 @@ send:
         error = ip_output(so, m);
         break;
 
+    case AF_INET6:
+        m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
+                     sizeof(struct ip6);
+        m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
+                    sizeof(struct ip6);
+        ip6 = mtod(m, struct ip6 *);
+
+        ip6->ip_pl = tcpiph_save.ti_len;
+        ip6->ip_dst = tcpiph_save.ti_dst6;
+        ip6->ip_src = tcpiph_save.ti_src6;
+        ip6->ip_nh = tcpiph_save.ti_nh6;
+
+        error = ip6_output(so, m, 0);
+        break;
+
     default:
         g_assert_not_reached();
     }
diff --git a/tcp_subr.c b/tcp_subr.c
index 0dae1da..fe19cf7 100644
--- a/tcp_subr.c
+++ b/tcp_subr.c
@@ -86,6 +86,15 @@ void tcp_template(struct tcpcb *tp)
         n->ti_dport = so->so_lport;
         break;
 
+    case AF_INET6:
+        n->ti_nh6 = IPPROTO_TCP;
+        n->ti_len = htons(sizeof(struct tcphdr));
+        n->ti_src6 = so->so_faddr6;
+        n->ti_dst6 = so->so_laddr6;
+        n->ti_sport = so->so_fport6;
+        n->ti_dport = so->so_lport6;
+        break;
+
     default:
         g_assert_not_reached();
     }
@@ -159,6 +168,10 @@ void tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
             xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, uint32_t);
             xchg(ti->ti_dport, ti->ti_sport, uint16_t);
             break;
+        case AF_INET6:
+            xchg(ti->ti_dst6, ti->ti_src6, struct in6_addr);
+            xchg(ti->ti_dport, ti->ti_sport, uint16_t);
+            break;
         default:
             g_assert_not_reached();
         }
@@ -185,6 +198,7 @@ void tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
 
     struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
     struct ip *ip;
+    struct ip6 *ip6;
 
     switch (af) {
     case AF_INET:
@@ -204,7 +218,21 @@ void tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
             ip->ip_ttl = IPDEFTTL;
         }
 
-        (void)ip_output((struct socket *)0, m);
+        ip_output(NULL, m);
+        break;
+
+    case AF_INET6:
+        m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
+                     sizeof(struct ip6);
+        m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
+                    sizeof(struct ip6);
+        ip6 = mtod(m, struct ip6 *);
+        ip6->ip_pl = tlen;
+        ip6->ip_dst = tcpiph_save.ti_dst6;
+        ip6->ip_src = tcpiph_save.ti_src6;
+        ip6->ip_nh = tcpiph_save.ti_nh6;
+
+        ip6_output(NULL, m, 0);
         break;
 
     default:
@@ -227,7 +255,7 @@ struct tcpcb *tcp_newtcpcb(struct socket *so)
 
     memset((char *)tp, 0, sizeof(struct tcpcb));
     tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp;
-    tp->t_maxseg = TCP_MSS;
+    tp->t_maxseg = (so->so_ffamily == AF_INET) ? TCP_MSS : TCP6_MSS;
 
     tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE | TF_REQ_TSTMP) : 0;
     tp->t_socket = so;
diff --git a/tcpip.h b/tcpip.h
index edc4ed1..384b508 100644
--- a/tcpip.h
+++ b/tcpip.h
@@ -45,6 +45,12 @@ struct tcpiphdr {
             uint8_t ih_x1; /* (unused) */
             uint8_t ih_pr; /* protocol */
         } ti_i4;
+        struct {
+            struct in6_addr ih_src;
+            struct in6_addr ih_dst;
+            uint8_t ih_x1;
+            uint8_t ih_nh;
+        } ti_i6;
     } ti;
     uint16_t ti_x0;
     uint16_t ti_len; /* protocol length */
@@ -54,6 +60,9 @@ struct tcpiphdr {
 #define ti_pr ti.ti_i4.ih_pr
 #define ti_src ti.ti_i4.ih_src
 #define ti_dst ti.ti_i4.ih_dst
+#define ti_src6 ti.ti_i6.ih_src
+#define ti_dst6 ti.ti_i6.ih_dst
+#define ti_nh6 ti.ti_i6.ih_nh
 #define ti_sport ti_t.th_sport
 #define ti_dport ti_t.th_dport
 #define ti_seq ti_t.th_seq