slirp: Forward ICMP echo requests via unprivileged socketsv0.15.0-rc0

Linux 3.0 gained support for unprivileged ICMP ping sockets. Use this
feature to forward guest pings to the outer world. The host admin has to
set the ping_group_range in order to grant access to those sockets. To
allow ping for the users group (GID 100):

echo 100 100 > /proc/sys/net/ipv4/ping_group_range

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/socket.c b/socket.c
index c920000..00b6bc2 100644
--- a/socket.c
+++ b/socket.c
@@ -65,6 +65,8 @@ void sofree(struct socket *so)
         slirp->tcp_last_so = &slirp->tcb;
     } else if (so == slirp->udp_last_so) {
         slirp->udp_last_so = &slirp->udb;
+    } else if (so == slirp->icmp_last_so) {
+        slirp->icmp_last_so = &slirp->icmp;
     }
     m_free(so->so_m);