slirp updates

Andrew Oates (1):
   slirp: fix ICMP handling on macOS hosts
 
 Gavin Grant (1):
   slirp: Propagate host TCP RST packet to the guest after socket
     disconnected
 
 Peter Maydell (1):
   slirp: document mbuf pointers and sizes
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Merge remote-tracking branch 'remotes/thibault/tags/samuel-thibault' into staging

slirp updates

Andrew Oates (1):
  slirp: fix ICMP handling on macOS hosts

Gavin Grant (1):
  slirp: Propagate host TCP RST packet to the guest after socket
    disconnected

Peter Maydell (1):
  slirp: document mbuf pointers and sizes

# gpg: Signature made Sun 07 Oct 2018 19:04:13 BST
# gpg:                using RSA key E3F65A9E9560DB4C
# gpg: Good signature from "Samuel Thibault <samuel.thibault@aquilenet.fr>"
# gpg:                 aka "Samuel Thibault <sthibault@debian.org>"
# gpg:                 aka "Samuel Thibault <samuel.thibault@gnu.org>"
# gpg:                 aka "Samuel Thibault <samuel.thibault@inria.fr>"
# gpg:                 aka "Samuel Thibault <samuel.thibault@labri.fr>"
# gpg:                 aka "Samuel Thibault <samuel.thibault@ens-lyon.org>"
# gpg:                 aka "Samuel Thibault <samuel.thibault@u-bordeaux.fr>"
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 900C B024 B679 31D4 0F82  304B D017 8C76 7D06 9EE6
#      Subkey fingerprint: 33FA 7B64 6195 01F8 CE9C  8F97 E3F6 5A9E 9560 DB4C

* remotes/thibault/tags/samuel-thibault:
  slirp: Propagate host TCP RST packet to the guest after socket disconnected
  slirp: fix ICMP handling on macOS hosts
  slirp: document mbuf pointers and sizes

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

slirp/ip_icmp.c

@@ -420,7 +420,32 @@ void icmp_receive(struct socket *so)
     icp = mtod(m, struct icmp *);
 
     id = icp->icmp_id;
-    len = qemu_recv(so->s, icp, m->m_len, 0);
+    len = qemu_recv(so->s, icp, M_ROOM(m), 0);
+    /*
+     * The behavior of reading SOCK_DGRAM+IPPROTO_ICMP sockets is inconsistent
+     * between host OSes.  On Linux, only the ICMP header and payload is
+     * included.  On macOS/Darwin, the socket acts like a raw socket and
+     * includes the IP header as well.  On other BSDs, SOCK_DGRAM+IPPROTO_ICMP
+     * sockets aren't supported at all, so we treat them like raw sockets.  It
+     * isn't possible to detect this difference at runtime, so we must use an
+     * #ifdef to determine if we need to remove the IP header.
+     */
+#ifdef CONFIG_BSD
+    if (len >= sizeof(struct ip)) {
+        struct ip *inner_ip = mtod(m, struct ip *);
+        int inner_hlen = inner_ip->ip_hl << 2;
+        if (inner_hlen > len) {
+            len = -1;
+            errno = -EINVAL;
+        } else {
+            len -= inner_hlen;
+            memmove(icp, (unsigned char *)icp + inner_hlen, len);
+        }
+    } else {
+      len = -1;
+      errno = -EINVAL;
+    }
+#endif
     icp->icmp_id = id;
 
     m->m_data -= hlen;

slirp/mbuf.c

@@ -151,7 +151,7 @@ m_cat(struct mbuf *m, struct mbuf *n)
 void
 m_inc(struct mbuf *m, int size)
 {
-    int datasize;
+    int gapsize;
 
     /* some compilers throw up on gotos.  This one we can fake. */
     if (M_ROOM(m) > size) {
@@ -159,17 +159,17 @@ m_inc(struct mbuf *m, int size)
     }
 
     if (m->m_flags & M_EXT) {
-        datasize = m->m_data - m->m_ext;
+        gapsize = m->m_data - m->m_ext;
-        m->m_ext = g_realloc(m->m_ext, size + datasize);
+        m->m_ext = g_realloc(m->m_ext, size + gapsize);
     } else {
-        datasize = m->m_data - m->m_dat;
+        gapsize = m->m_data - m->m_dat;
-        m->m_ext = g_malloc(size + datasize);
+        m->m_ext = g_malloc(size + gapsize);
         memcpy(m->m_ext, m->m_dat, m->m_size);
         m->m_flags |= M_EXT;
     }
 
-    m->m_data = m->m_ext + datasize;
+    m->m_data = m->m_ext + gapsize;
-    m->m_size = size + datasize;
+    m->m_size = size + gapsize;
 }
 
 

slirp/mbuf.h

@@ -47,6 +47,19 @@
  * free the m_ext.  This is inefficient memory-wise, but who cares.
  */
 
+/*
+ * mbufs allow to have a gap between the start of the allocated buffer (m_ext if
+ * M_EXT is set, m_dat otherwise) and the in-use data:
+ *
+ *  |--gapsize----->|---m_len------->
+ *  |----------m_size------------------------------>
+ *                  |----M_ROOM-------------------->
+ *                                   |-M_FREEROOM-->
+ *
+ *  ^               ^                               ^
+ *  m_dat/m_ext     m_data                          end of buffer
+ */
+
 /*
  * How much room is in the mbuf, from m_data to the end of the mbuf
  */

slirp/socket.c

@@ -204,12 +204,19 @@ soread(struct socket *so)
 			return 0;
 		else {
 			int err;
-			socklen_t slen = sizeof err;
+			socklen_t elen = sizeof err;
+			struct sockaddr_storage addr;
+			struct sockaddr *paddr = (struct sockaddr *) &addr;
+			socklen_t alen = sizeof addr;
 
 			err = errno;
 			if (nn == 0) {
+				if (getpeername(so->s, paddr, &alen) < 0) {
+					err = errno;
+				} else {
 					getsockopt(so->s, SOL_SOCKET, SO_ERROR,
-					   &err, &slen);
+						&err, &elen);
+				}
 			}
 
 			DEBUG_MISC((dfd, " --- soread() disconnected, nn = %d, errno = %d-%s\n", nn, errno,strerror(errno)));