ofproto-dpif-xlate: makes OVS native tunneling honor tunnel-specified…

… source addresses

It makes OVS native tunneling honor tunnel-specified source addresses,
in the same way that Linux kernel tunneling honors them.

This patch made valid tun_src specified by flow-action can be used for
tunnel_src of packet. add a "local" property for a route entry and enhance
the priority of local route higher than user route.
Like the kernel space when lookup the route, if there are tun_src specified
by flow-action or port options. Check the tun_src wheather is a local
address, then lookup the route.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: frank.zeng <frank.zeng@ucloud.cn>
Signed-off-by: Ben Pfaff <blp@ovn.org>

lib/ovs-router.c

@@ -66,6 +66,7 @@ struct ovs_router_entry {
     struct in6_addr src_addr;
     uint8_t plen;
     uint8_t priority;
+    bool local;
     uint32_t mark;
 };
 
@@ -110,13 +111,28 @@ ovs_router_lookup(uint32_t mark, const struct in6_addr *ip6_dst,
     const struct cls_rule *cr;
     struct flow flow = {.ipv6_dst = *ip6_dst, .pkt_mark = mark};
 
+    if (src && ipv6_addr_is_set(src)) {
+        const struct cls_rule *cr_src;
+        struct flow flow_src = {.ipv6_dst = *src, .pkt_mark = mark};
+
+        cr_src = classifier_lookup(&cls, OVS_VERSION_MAX, &flow_src, NULL);
+        if (cr_src) {
+            struct ovs_router_entry *p_src = ovs_router_entry_cast(cr_src);
+            if (!p_src->local) {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
     cr = classifier_lookup(&cls, OVS_VERSION_MAX, &flow, NULL);
     if (cr) {
         struct ovs_router_entry *p = ovs_router_entry_cast(cr);
 
         ovs_strlcpy(output_bridge, p->output_bridge, IFNAMSIZ);
         *gw = p->gw;
-        if (src) {
+        if (src && !ipv6_addr_is_set(src)) {
             *src = p->src_addr;
         }
         return true;
@@ -197,7 +213,7 @@ get_src_addr(const struct in6_addr *ip6_dst,
 }
 
 static int
-ovs_router_insert__(uint32_t mark, uint8_t priority,
+ovs_router_insert__(uint32_t mark, uint8_t priority, bool local,
                     const struct in6_addr *ip6_dst,
                     uint8_t plen, const char output_bridge[],
                     const struct in6_addr *gw)
@@ -217,6 +233,7 @@ ovs_router_insert__(uint32_t mark, uint8_t priority,
     p->mark = mark;
     p->nw_addr = match.flow.ipv6_dst;
     p->plen = plen;
+    p->local = local;
     p->priority = priority;
     err = get_src_addr(ip6_dst, output_bridge, &p->src_addr);
     if (err && ipv6_addr_is_set(gw)) {
@@ -249,10 +266,12 @@ ovs_router_insert__(uint32_t mark, uint8_t priority,
 
 void
 ovs_router_insert(uint32_t mark, const struct in6_addr *ip_dst, uint8_t plen,
-                  const char output_bridge[], const struct in6_addr *gw)
+                  bool local, const char output_bridge[], 
+                  const struct in6_addr *gw)
 {
     if (use_system_routing_table) {
-        ovs_router_insert__(mark, plen, ip_dst, plen, output_bridge, gw);
+        uint8_t priority = local ? plen + 64 : plen;
+        ovs_router_insert__(mark, priority, local, ip_dst, plen, output_bridge, gw);
     }
 }
 
@@ -360,7 +379,7 @@ ovs_router_add(struct unixctl_conn *conn, int argc,
         }
     }
 
-    err = ovs_router_insert__(mark, plen + 32, &ip6, plen, argv[2], &gw6);
+    err = ovs_router_insert__(mark, plen + 32, false, &ip6, plen, argv[2], &gw6);
     if (err) {
         unixctl_command_reply_error(conn, "Error while inserting route.");
     } else {
@@ -409,7 +428,7 @@ ovs_router_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
     ds_put_format(&ds, "Route Table:\n");
     CLS_FOR_EACH(rt, cr, &cls) {
         uint8_t plen;
-        if (rt->priority == rt->plen) {
+        if (rt->priority == rt->plen || rt->local) {
             ds_put_format(&ds, "Cached: ");
         } else {
             ds_put_format(&ds, "User: ");
@@ -431,6 +450,9 @@ ovs_router_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
         }
         ds_put_format(&ds, " SRC ");
         ipv6_format_mapped(&rt->src_addr, &ds);
+        if (rt->local) {
+            ds_put_format(&ds, " local");
+        }
         ds_put_format(&ds, "\n");
     }
     unixctl_command_reply(conn, ds_cstr(&ds));
@@ -441,7 +463,7 @@ static void
 ovs_router_lookup_cmd(struct unixctl_conn *conn, int argc,
                       const char *argv[], void *aux OVS_UNUSED)
 {
-    struct in6_addr gw, src;
+    struct in6_addr gw, src = in6addr_any;
     char iface[IFNAMSIZ];
     struct in6_addr ip6;
     unsigned int plen;

lib/ovs-router.h

@@ -31,7 +31,7 @@ bool ovs_router_lookup(uint32_t mark, const struct in6_addr *ip_dst,
                        struct in6_addr *src, struct in6_addr *gw);
 void ovs_router_init(void);
 void ovs_router_insert(uint32_t mark, const struct in6_addr *ip_dst,
-                       uint8_t plen,
+                       uint8_t plen, bool local,
                        const char output_bridge[], const struct in6_addr *gw);
 void ovs_router_flush(void);
 

lib/route-table.c

@@ -47,6 +47,7 @@ VLOG_DEFINE_THIS_MODULE(route_table);
 struct route_data {
     /* Copied from struct rtmsg. */
     unsigned char rtm_dst_len;
+    bool local;
 
     /* Extracted from Netlink attributes. */
     struct in6_addr rta_dst; /* 0 if missing. */
@@ -245,6 +246,7 @@ route_table_parse(struct ofpbuf *buf, struct route_table_msg *change)
         }
         change->nlmsg_type     = nlmsg->nlmsg_type;
         change->rd.rtm_dst_len = rtm->rtm_dst_len + (ipv4 ? 96 : 0);
+        change->rd.local = rtm->rtm_type == RTN_LOCAL;
         if (attrs[RTA_OIF]) {
             rta_oif = nl_attr_get_u32(attrs[RTA_OIF]);
 
@@ -307,7 +309,7 @@ route_table_handle_msg(const struct route_table_msg *change)
         const struct route_data *rd = &change->rd;
 
         ovs_router_insert(rd->mark, &rd->rta_dst, rd->rtm_dst_len,
-                          rd->ifname, &rd->rta_gw);
+                          rd->local, rd->ifname, &rd->rta_gw);
     }
 }
 

ofproto/ofproto-dpif-sflow.c

@@ -474,7 +474,7 @@ sflow_choose_agent_address(const char *agent_device,
              */
             ip = ss_get_address(&ss);
 
-            struct in6_addr src, gw;
+            struct in6_addr gw, src = in6addr_any;
             char name[IFNAMSIZ];
             if (ovs_router_lookup(0, &ip, name, &src, &gw)) {
                 goto success;

ofproto/ofproto-dpif-xlate.c

@@ -3320,6 +3320,10 @@ native_tunnel_output(struct xlate_ctx *ctx, const struct xport *xport,
     /* Backup flow & base_flow data. */
     memcpy(&old_base_flow, &ctx->base_flow, sizeof old_base_flow);
     memcpy(&old_flow, &ctx->xin->flow, sizeof old_flow);
+
+    if (flow->tunnel.ip_src) {
+        in6_addr_set_mapped_ipv4(&s_ip6, flow->tunnel.ip_src);
+    }
 
     err = tnl_route_lookup_flow(ctx, flow, &d_ip6, &s_ip6, &out_dev);
     if (err) {