[Qemu-devel] [PATCH v2] slirp: Handle whole 127.0.0.0/8 network as local addresses.

[Anders Waldenborg <anders@0x63.nu>]

Changes so translation of remote address to the host's ip address in
the virtual network happens for all addresses in the 127.0.0.0/8
network, not just 127.0.0.1.

This fixes so that hostfwd bound to addresses such as 127.0.0.2 works.

Signed-off-by: Anders Waldenborg <anders@0x63.nu>
---

Thanks for the review!

Patch updated according to comments.

Notice that the surrounding code in tcp_subr.c uses tabs for
indentation. Should I still use space as the coding style mandates
(and which makes checkpatch happy)?

 slirp/main.h     |    1 +
 slirp/slirp.c    |    3 +++
 slirp/tcp_subr.c |    6 ++++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/slirp/main.h b/slirp/main.h
index 028df4b..bf601e2 100644
--- a/slirp/main.h
+++ b/slirp/main.h
@@ -31,6 +31,7 @@ extern char *exec_shell;
 extern u_int curtime;
 extern fd_set *global_readfds, *global_writefds, *global_xfds;
 extern struct in_addr loopback_addr;
+extern in_addr_t loopback_mask;
 extern char *username;
 extern char *socket_path;
 extern int towrite_max;
diff --git a/slirp/slirp.c b/slirp/slirp.c
index 90473eb..9787104 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -29,6 +29,8 @@
 
 /* host loopback address */
 struct in_addr loopback_addr;
+/* host loopback network mask */
+in_addr_t loopback_mask;
 
 /* emulated hosts use the MAC addr 52:55:IP:IP:IP:IP */
 static const uint8_t special_ethaddr[ETH_ALEN] = {
@@ -191,6 +193,7 @@ static void slirp_init_once(void)
 #endif
 
     loopback_addr.s_addr = htonl(INADDR_LOOPBACK);
+    loopback_mask = htonl(IN_CLASSA_NET);
 }
 
 static void slirp_state_save(QEMUFile *f, void *opaque);
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index 0a545c4..064b5e8 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -435,8 +435,10 @@ tcp_connect(struct socket *inso)
 	so->so_fport = addr.sin_port;
 	so->so_faddr = addr.sin_addr;
 	/* Translate connections from localhost to the real hostname */
-	if (so->so_faddr.s_addr == 0 || so->so_faddr.s_addr == loopback_addr.s_addr)
-	   so->so_faddr = slirp->vhost_addr;
+    if (so->so_faddr.s_addr == 0 ||
+        (so->so_faddr.s_addr & loopback_mask) ==
+        (loopback_addr.s_addr & loopback_mask))
+        so->so_faddr = slirp->vhost_addr;
 
 	/* Close the accept() socket, set right state */
 	if (inso->so_state & SS_FACCEPTONCE) {
-- 
1.7.2.5