Changeset 52798 in vbox

Timestamp:

Sep 21, 2014 9:19:38 PM (10 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

96193

Message:

NAT: when outgoing connect(2) fails decide what to do based on the
errno. The code to call icmp_error() is a bit icky because
tcp_input() vivisects incoming datagram and original mbuf can't be
used.

Location:

trunk/src/VBox/Devices/Network/slirp

Files:

• slirp.c (modified) (1 diff)
• slirp.h (modified) (1 diff)
• socket.c (modified) (1 diff)
• socket.h (modified) (1 diff)
• tcp_input.c (modified) (8 diffs)

trunk/src/VBox/Devices/Network/slirp/slirp.c

@@ -1011 +1011 @@
             if (sockerr != 0)
             {
-                /* "continue" tcp_input() to reject connection from guest */
-                so->so_state = SS_NOFDREF;
-                TCP_INPUT(pData, NULL, 0, so);
+                tcp_fconnect_failed(pData, so, sockerr);
                 ret = slirpVerifyAndFreeSocket(pData, so);
                 Assert(ret == 1); /* freed */

trunk/src/VBox/Devices/Network/slirp/slirp.h

@@ -321 +321 @@
 int tcp_reass (PNATState, struct tcpcb *, struct tcphdr *, int *, struct mbuf *);
 void tcp_input (PNATState, register struct mbuf *, int, struct socket *);
+void tcp_fconnect_failed(PNATState, struct socket *, int);
 void tcp_dooptions (PNATState, struct tcpcb *, u_char *, int, struct tcpiphdr *);
 void tcp_xmit_timer (PNATState, register struct tcpcb *, int);

trunk/src/VBox/Devices/Network/slirp/socket.c

@@ -214 +214 @@
         m_freem(pData, so->so_m);
         so->so_m = NULL;
+    }
+
+    if (so->so_ohdr != NULL)
+    {
+        RTMemFree(so->so_ohdr);
+        so->so_ohdr = NULL;
     }
 

trunk/src/VBox/Devices/Network/slirp/socket.h

@@ -59 +59 @@
     struct tcpiphdr *so_ti;      /* Pointer to the original ti within
                                   * so_mconn, for non-blocking connections */
+    uint8_t         *so_ohdr;    /* unmolested IP header of the datagram in so_m */
     int             so_urgc;
     struct in_addr  so_faddr;    /* foreign host table entry */

trunk/src/VBox/Devices/Network/slirp/tcp_input.c

@@ -290 +290 @@
 tcp_input(PNATState pData, register struct mbuf *m, int iphlen, struct socket *inso)
 {
-    struct ip save_ip, *ip;
+    struct ip *ip, *save_ip;
     register struct tcpiphdr *ti;
     caddr_t optp = NULL;
@@ -303 +303 @@
     u_long tiwin;
 /*  int ts_present = 0; */
+    size_t ohdrlen;
+    uint8_t ohdr[60 + 8]; /* max IP header plus 8 bytes of payload for icmp */
+
     STAM_PROFILE_START(&pData->StatTCP_input, counter_input);
 
@@ -324 +327 @@
         tp = sototcpcb(so);
         m = so->so_m;
-
         so->so_m = 0;
+
+        if (RT_LIKELY(so->so_ohdr != NULL))
+        {
+            RTMemFree(so->so_ohdr);
+            so->so_ohdr = NULL;
+        }
+
         ti = so->so_ti;
 
@@ -347 +356 @@
 
     tcpstat.tcps_rcvtotal++;
+
+    ip = mtod(m, struct ip *);
+
+    /* ip_input() subtracts iphlen from ip::ip_len */
+    AssertStmt((ip->ip_len + iphlen == m_length(m, NULL)), goto drop);
+    if (RT_UNLIKELY(ip->ip_len < sizeof(struct tcphdr)))
+    {
+        /* tcps_rcvshort++; */
+        goto drop;
+    }
+
+    /*
+     * Save a copy of the IP header in case we want to restore it for
+     * sending an ICMP error message in response.
+     *
+     * XXX: This function should really be fixed to not strip IP
+     * options, to not overwrite IP header and to use "tlen" local
+     * variable (instead of ti->ti_len), then "m" could be passed to
+     * icmp_error() directly.
+     */
+    ohdrlen = iphlen + 8;
+    m_copydata(m, 0, ohdrlen, (caddr_t)ohdr);
+    save_ip = (struct ip *)ohdr;
+    save_ip->ip_len += iphlen;  /* undo change by ip_input() */
+
+
     /*
      * Get IP and TCP header together in first mbuf.
@@ -357 +392 @@
         iphlen = sizeof(struct ip);
     }
-    /* XXX Check if too short */
-
-
-    /*
-     * 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 *);
-    /*
-     * (vvl) ip_input substracts IP header length from ip->ip_len value.
-     * here we do the test the same as input method of UDP protocol.
-     */
-    Assert((ip->ip_len + iphlen == m_length(m, NULL)));
-    save_ip = *ip;
-    save_ip.ip_len+= iphlen;
 
     /*
@@ -802 +822 @@
                     m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
                     m->m_len  += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);
-                    *ip = save_ip;
+                    *ip = *save_ip;
                     icmp_error(pData, m, ICMP_UNREACH, code, 0, strerror(errno));
                     tp->t_socket->so_m = NULL;
@@ -818 +838 @@
                 so->so_m = m;
                 so->so_ti = ti;
+                so->so_ohdr = RTMemDup(ohdr, ohdrlen);
                 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
                 TCP_STATE_SWITCH_TO(tp, TCPS_SYN_RECEIVED);
@@ -1743 +1764 @@
 }
 
+
+void
+tcp_fconnect_failed(PNATState pData, struct socket *so, int sockerr)
+{
+    struct tcpcb *tp;
+    int code;
+
+    Log2(("NAT: connect error %d %R[natsock]\n", sockerr, so));
+
+    Assert(so->so_state & SS_ISFCONNECTING);
+    so->so_state = SS_NOFDREF;
+
+    if (sockerr == ECONNREFUSED || sockerr == ECONNRESET)
+    {
+        /* hand off to tcp_input():cont_conn to send RST */
+        TCP_INPUT(pData, NULL, 0, so);
+        return;
+    }
+
+    tp = sototcpcb(so);
+    if (RT_UNLIKELY(tp == NULL)) /* should never happen */
+    {
+        LogRel(("NAT: tp == NULL %R[natsock]\n", so));
+        sofree(pData, so);
+        return;
+    }
+
+    if (sockerr == ENETUNREACH || sockerr == ENETDOWN)
+        code = ICMP_UNREACH_NET;
+    else if (sockerr == EHOSTUNREACH || sockerr == EHOSTDOWN)
+        code = ICMP_UNREACH_HOST;
+    else
+        code = -1;
+
+    if (code >= 0)
+    {
+        struct ip *oip;
+        size_t ohdrlen;
+        struct mbuf *m;
+
+        if (RT_UNLIKELY(so->so_ohdr == NULL))
+            goto out;
+
+        oip = (struct ip *)so->so_ohdr;
+        ohdrlen = oip->ip_hl * 4 + 8;
+
+        m = m_gethdr(pData, M_NOWAIT, MT_HEADER);
+        if (RT_UNLIKELY(m == NULL))
+            goto out;
+
+        m_copyback(pData, m, 0, ohdrlen, (caddr_t)so->so_ohdr);
+        m->m_pkthdr.header = mtod(m, void *);
+
+        icmp_error(pData, m, ICMP_UNREACH, code, 0, NULL);
+    }
+
+  out:
+    tcp_close(pData, tp);
+}
+
+
 void
 tcp_dooptions(PNATState pData, struct tcpcb *tp, u_char *cp, int cnt, struct tcpiphdr *ti)