User Networking: Enable removal of redirections

Using the new host_net_redir command you can easily create redirections
on the fly while your VM is running.

While that's great, it's missing the removal of redirections, in case you
want to have a port closed again at a later point in time.

This patch adds support for removal of redirections.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

2 files changed, 24 insertions, 0 deletions

diff --git a/slirp/libslirp.h b/slirp/libslirp.h
index a1cd70e..6fc2c32 100644
--- a/slirp/libslirp.h
+++ b/slirp/libslirp.h
@@ -18,6 +18,7 @@ void slirp_input(const uint8_t *pkt, int pkt_len);
 int slirp_can_output(void);
 void slirp_output(const uint8_t *pkt, int pkt_len);
 
+int slirp_redir_rm(int is_udp, int host_port);
 int slirp_redir(int is_udp, int host_port,
                 struct in_addr guest_addr, int guest_port);
 int slirp_add_exec(int do_pty, const void *args, int addr_low_byte,
diff --git a/slirp/slirp.c b/slirp/slirp.c
index 04d3ded..33397c0 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -734,6 +734,29 @@ void if_encap(const uint8_t *ip_data, int ip_data_len)
     }
 }
 
+/* Unlistens a redirection
+ *
+ * Return value: number of redirs removed */
+int slirp_redir_rm(int is_udp, int host_port)
+{
+    struct socket *so;
+    struct socket *head = (is_udp ? &udb : &tcb);
+    int fport = htons(host_port);
+    int n = 0;
+
+ loop_again:
+    for (so = head->so_next; so != head; so = so->so_next) {
+        if (so->so_fport == fport) {
+            close(so->s);
+            sofree(so);
+            n++;
+            goto loop_again;
+        }
+    }
+
+    return n;
+}
+
 int slirp_redir(int is_udp, int host_port,
                 struct in_addr guest_addr, int guest_port)
 {