interface-ip: add support for excluding interfaces in host route lookup

When adding host routes needed for an interface to communicate, it may be
necessary to skip the interface itself, in case it provides a default route.
This helps with avoiding accidental loops

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/interface-ip.c b/interface-ip.c
index 54d5fe029d2babecfe8719eaf3d3c0d54734d5d4..585cb6f1d6736b4c4df8b84f344e15e000e6120d 100644 (file)
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -257,12 +257,19 @@ interface_ip_find_route_target(struct interface *iface, union if_addr *a,
 }
 
 struct interface *
-interface_ip_add_target_route(union if_addr *addr, bool v6, struct interface *iface)
+interface_ip_add_target_route(union if_addr *addr, bool v6, struct interface *iface,
+                             bool exclude)
 {
        struct device_route *route, *r_next = NULL;
        bool defaultroute_target = false;
        union if_addr addr_zero;
        int addrsize = v6 ? sizeof(addr->in6) : sizeof(addr->in);
+       struct interface *exclude_iface = NULL;
+
+       if (exclude) {
+               exclude_iface = iface;
+               iface = NULL;
+       }
 
        memset(&addr_zero, 0, sizeof(addr_zero));
        if (memcmp(&addr_zero, addr, addrsize) == 0)
@@ -278,6 +285,9 @@ interface_ip_add_target_route(union if_addr *addr, bool v6, struct interface *if
                interface_ip_find_route_target(iface, addr, v6, &r_next);
        } else {
                vlist_for_each_element(&interfaces, iface, node) {
+                       if (iface == exclude_iface)
+                               continue;
+
                        /* look for locally addressable target first */
                        if (interface_ip_find_addr_target(iface, addr, v6))
                                return iface;

diff --git a/interface-ip.h b/interface-ip.h
index b17ad94c5159a8720fe2044573aac7dedf0fcf65..8843349b2de8227df6d2eabcfc99aa27b47fc04b 100644 (file)
--- a/interface-ip.h
+++ b/interface-ip.h
@@ -184,7 +184,8 @@ void interface_ip_flush(struct interface_ip_settings *ip);
 void interface_ip_set_enabled(struct interface_ip_settings *ip, bool enabled);
 void interface_ip_update_metric(struct interface_ip_settings *ip, int metric);
 
-struct interface *interface_ip_add_target_route(union if_addr *addr, bool v6, struct interface *iface);
+struct interface *interface_ip_add_target_route(union if_addr *addr, bool v6, struct interface *iface,
+                                               bool exclude);
 
 struct device_prefix* interface_ip_add_device_prefix(struct interface *iface,
                struct in6_addr *addr, uint8_t length, time_t valid_until, time_t preferred_until,

diff --git a/proto-shell.c b/proto-shell.c
index e20d53961592d614123c03fa7057d3d31f061fb2..9cdbc7fde362ac4ea112743bfcd8831bc38d6eca 100644 (file)
--- a/proto-shell.c
+++ b/proto-shell.c
@@ -129,7 +129,7 @@ proto_shell_update_host_dep(struct proto_shell_dependency *dep)
        }
 
        if (!dep->any)
-               iface = interface_ip_add_target_route(&dep->host, dep->v6, iface);
+               iface = interface_ip_add_target_route(&dep->host, dep->v6, iface, false);
 
        if (!iface)
                goto out;

diff --git a/ubus.c b/ubus.c
index a38617928b415c7540338684a1402785d83dd416..2876e7d173fb5fef23732171f3aa431df4ce9f29 100644 (file)
--- a/ubus.c
+++ b/ubus.c
@@ -54,6 +54,7 @@ enum {
        HR_TARGET,
        HR_V6,
        HR_INTERFACE,
+       HR_EXCLUDE,
        __HR_MAX
 };
 
@@ -61,6 +62,7 @@ static const struct blobmsg_policy route_policy[__HR_MAX] = {
        [HR_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
        [HR_V6] = { .name = "v6", .type = BLOBMSG_TYPE_BOOL },
        [HR_INTERFACE] = { .name = "interface", .type = BLOBMSG_TYPE_STRING },
+       [HR_EXCLUDE] = { .name = "exclude", .type = BLOBMSG_TYPE_BOOL },
 };
 
 static int
@@ -72,6 +74,7 @@ netifd_add_host_route(struct ubus_context *ctx, struct ubus_object *obj,
        struct interface *iface = NULL;
        union if_addr a;
        bool v6 = false;
+       bool exclude = false;
 
        blobmsg_parse(route_policy, __HR_MAX, tb, blob_data(msg), blob_len(msg));
        if (!tb[HR_TARGET])
@@ -80,6 +83,9 @@ netifd_add_host_route(struct ubus_context *ctx, struct ubus_object *obj,
        if (tb[HR_V6])
                v6 = blobmsg_get_bool(tb[HR_V6]);
 
+       if (tb[HR_EXCLUDE])
+               exclude = blobmsg_get_bool(tb[HR_EXCLUDE]);
+
        if (tb[HR_INTERFACE])
                iface = vlist_find(&interfaces, blobmsg_data(tb[HR_INTERFACE]), iface, node);
 
@@ -87,8 +93,7 @@ netifd_add_host_route(struct ubus_context *ctx, struct ubus_object *obj,
        if (!inet_pton(v6 ? AF_INET6 : AF_INET, blobmsg_data(tb[HR_TARGET]), &a))
                return UBUS_STATUS_INVALID_ARGUMENT;
 
-
-       iface = interface_ip_add_target_route(&a, v6, iface);
+       iface = interface_ip_add_target_route(&a, v6, iface, exclude);
        if (!iface)
                return UBUS_STATUS_NOT_FOUND;