From a5fd24aa6d0f26aeb9f15b24daa2d68427631c40 Mon Sep 17 00:00:00 2001
From: Guillaume Subiron <maethor@subiron.org>
Date: Sat, 19 Dec 2015 22:25:00 +0100
Subject: slirp: Factorizing and cleaning solookup()

solookup() was only compatible with TCP. Having the socket list in
argument, it is now compatible with UDP too.

Some optimization code is factorized inside the function (the function
look at the last returned result before browsing the complete socket
list).

This prepares for IPv6 support.

Signed-off-by: Guillaume Subiron <maethor@subiron.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 slirp/socket.c    | 37 ++++++++++++++++++++++++-------------
 slirp/socket.h    |  5 +++--
 slirp/tcp_input.c | 13 +++----------
 slirp/udp.c       | 21 ++-------------------
 4 files changed, 32 insertions(+), 44 deletions(-)

diff --git a/slirp/socket.c b/slirp/socket.c
index d1034fb536..8f73e906e2 100644
--- a/slirp/socket.c
+++ b/slirp/socket.c
@@ -16,23 +16,34 @@ static void sofcantrcvmore(struct socket *so);
 static void sofcantsendmore(struct socket *so);
 
 struct socket *
-solookup(struct socket *head, struct in_addr laddr, u_int lport,
+solookup(struct socket **last, struct socket *head,
+         struct in_addr laddr, u_int lport,
          struct in_addr faddr, u_int fport)
 {
-	struct socket *so;
-
-	for (so = head->so_next; so != head; so = so->so_next) {
-		if (so->so_lport == lport &&
-		    so->so_laddr.s_addr == laddr.s_addr &&
-		    so->so_faddr.s_addr == faddr.s_addr &&
-		    so->so_fport == fport)
-		   break;
-	}
+    struct socket *so = *last;
+
+    /* Optimisation */
+    if (so != head &&
+            so->so_lport == lport &&
+            so->so_laddr.s_addr == laddr.s_addr &&
+            (!faddr.s_addr ||
+                (so->so_faddr.s_addr == faddr.s_addr &&
+                 so->so_fport == fport))) {
+        return so;
+    }
 
-	if (so == head)
-	   return (struct socket *)NULL;
-	return so;
+    for (so = head->so_next; so != head; so = so->so_next) {
+        if (so->so_lport == lport &&
+            so->so_laddr.s_addr == laddr.s_addr &&
+            (!faddr.s_addr ||
+                (so->so_faddr.s_addr == faddr.s_addr &&
+                 so->so_fport == fport))) {
+            *last = so;
+            return so;
+        }
+    }
 
+    return (struct socket *)NULL;
 }
 
 /*
diff --git a/slirp/socket.h b/slirp/socket.h
index b27bbb2c59..1c8c24c16b 100644
--- a/slirp/socket.h
+++ b/slirp/socket.h
@@ -87,8 +87,9 @@ struct socket {
 #define SS_HOSTFWD		0x1000	/* Socket describes host->guest forwarding */
 #define SS_INCOMING		0x2000	/* Connection was initiated by a host on the internet */
 
-struct socket * solookup(struct socket *, struct in_addr, u_int, struct in_addr, u_int);
-struct socket * socreate(Slirp *);
+struct socket *solookup(struct socket **, struct socket *,
+        struct in_addr, u_int, struct in_addr, u_int);
+struct socket *socreate(Slirp *);
 void sofree(struct socket *);
 int soread(struct socket *);
 void sorecvoob(struct socket *);
diff --git a/slirp/tcp_input.c b/slirp/tcp_input.c
index 4c3191d4fd..549206150c 100644
--- a/slirp/tcp_input.c
+++ b/slirp/tcp_input.c
@@ -320,16 +320,9 @@ tcp_input(struct mbuf *m, int iphlen, struct socket *inso)
 	 * Locate pcb for segment.
 	 */
 findso:
-	so = slirp->tcp_last_so;
-	if (so->so_fport != ti->ti_dport ||
-	    so->so_lport != ti->ti_sport ||
-	    so->so_laddr.s_addr != ti->ti_src.s_addr ||
-	    so->so_faddr.s_addr != ti->ti_dst.s_addr) {
-		so = solookup(&slirp->tcb, ti->ti_src, ti->ti_sport,
-			       ti->ti_dst, ti->ti_dport);
-		if (so)
-			slirp->tcp_last_so = so;
-	}
+	so = solookup(&slirp->tcp_last_so, &slirp->tcb,
+		      ti->ti_src, ti->ti_sport,
+		      ti->ti_dst, ti->ti_dport);
 
 	/*
 	 * If the state is CLOSED (i.e., TCB does not exist) then
diff --git a/slirp/udp.c b/slirp/udp.c
index 8203eb1bb2..126ef82a8e 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -151,25 +151,8 @@ udp_input(register struct mbuf *m, int iphlen)
 	/*
 	 * Locate pcb for datagram.
 	 */
-	so = slirp->udp_last_so;
-	if (so == &slirp->udb || so->so_lport != uh->uh_sport ||
-	    so->so_laddr.s_addr != ip->ip_src.s_addr) {
-		struct socket *tmp;
-
-		for (tmp = slirp->udb.so_next; tmp != &slirp->udb;
-		     tmp = tmp->so_next) {
-			if (tmp->so_lport == uh->uh_sport &&
-			    tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
-				so = tmp;
-				break;
-			}
-		}
-		if (tmp == &slirp->udb) {
-		  so = NULL;
-		} else {
-		  slirp->udp_last_so = so;
-		}
-	}
+	so = solookup(&slirp->udp_last_so, &slirp->udb,
+		      ip->ip_src, uh->uh_sport, (struct in_addr) {0}, 0);
 
 	if (so == NULL) {
 	  /*
-- 
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