inet: Add function to return route to a given host

The netlink message handling is modified from iproute.c in iproute2 package.

diff --git a/src/connman.h b/src/connman.h
index 492595d..f2fcecc 100644 (file)
--- a/src/connman.h
+++ b/src/connman.h
@@ -153,6 +153,10 @@ int __connman_refresh_rs_ipv6(struct connman_network *network, int index);
 
 GSList *__connman_inet_ipv6_get_prefixes(struct nd_router_advert *hdr,
                                        unsigned int length);
+typedef void (*connman_inet_addr_cb_t) (const char *src_address, int index,
+                                       void *user_data);
+int __connman_inet_get_route(const char *dst_address,
+                       connman_inet_addr_cb_t callback, void *user_data);
 
 struct __connman_inet_rtnl_handle {
        int                     fd;

diff --git a/src/inet.c b/src/inet.c
index c28c3e4..0c3109d 100644 (file)
--- a/src/inet.c
+++ b/src/inet.c
@@ -2174,6 +2174,155 @@ int __connman_inet_rtnl_addattr32(struct nlmsghdr *n, size_t maxlen, int type,
        return 0;
 }
 
+static int parse_rtattr(struct rtattr *tb[], int max,
+                       struct rtattr *rta, int len)
+{
+       memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+       while (RTA_OK(rta, len)) {
+               if ((rta->rta_type <= max) && (!tb[rta->rta_type]))
+                       tb[rta->rta_type] = rta;
+               rta = RTA_NEXT(rta, len);
+       }
+       if (len)
+               connman_error("Deficit %d, rta_len=%d", len, rta->rta_len);
+
+       return 0;
+}
+
+struct get_route_cb_data {
+       connman_inet_addr_cb_t callback;
+       void *user_data;
+};
+
+static void get_route_cb(struct nlmsghdr *answer, void *user_data)
+{
+       struct get_route_cb_data *data = user_data;
+       struct rtattr *tb[RTA_MAX+1];
+       struct rtmsg *r = NLMSG_DATA(answer);
+       int len, index = -1;
+       char abuf[256];
+       const char *addr = NULL;
+
+       DBG("answer %p data %p", answer, user_data);
+
+       if (answer == NULL)
+               goto out;
+
+       len = answer->nlmsg_len;
+
+       if (answer->nlmsg_type != RTM_NEWROUTE &&
+                               answer->nlmsg_type != RTM_DELROUTE) {
+               connman_error("Not a route: %08x %08x %08x",
+                       answer->nlmsg_len, answer->nlmsg_type,
+                       answer->nlmsg_flags);
+               goto out;
+       }
+
+       len -= NLMSG_LENGTH(sizeof(*r));
+       if (len < 0) {
+               connman_error("BUG: wrong nlmsg len %d", len);
+               goto out;
+       }
+
+       parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
+
+       if (tb[RTA_OIF] != NULL)
+               index = *(int *)RTA_DATA(tb[RTA_OIF]);
+
+       if (tb[RTA_GATEWAY] != NULL)
+               addr = inet_ntop(r->rtm_family,
+                               RTA_DATA(tb[RTA_GATEWAY]),
+                               abuf, sizeof(abuf));
+
+       DBG("addr %s index %d user %p", addr, index, data->user_data);
+
+out:
+       if (data != NULL && data->callback != NULL)
+               data->callback(addr, index, data->user_data);
+
+       g_free(data);
+
+       return;
+}
+
+/*
+ * Return the interface index that contains route to host.
+ */
+int __connman_inet_get_route(const char *dest_address,
+                       connman_inet_addr_cb_t callback, void *user_data)
+{
+       struct get_route_cb_data *data;
+       struct addrinfo hints, *rp;
+       struct __connman_inet_rtnl_handle *rth;
+       int err;
+
+       DBG("dest %s", dest_address);
+
+       if (dest_address == NULL)
+               return -EINVAL;
+
+       memset(&hints, 0, sizeof(hints));
+       hints.ai_family = AF_UNSPEC;
+       hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
+
+       err = getaddrinfo(dest_address, NULL, &hints, &rp);
+       if (err)
+               return -EINVAL;
+
+       rth = g_try_malloc0(sizeof(struct __connman_inet_rtnl_handle));
+       if (rth == NULL) {
+               freeaddrinfo(rp);
+               return -ENOMEM;
+       }
+
+       rth->req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
+       rth->req.n.nlmsg_flags = NLM_F_REQUEST;
+       rth->req.n.nlmsg_type = RTM_GETROUTE;
+       rth->req.u.r.rt.rtm_family = rp->ai_family;
+       rth->req.u.r.rt.rtm_table = 0;
+       rth->req.u.r.rt.rtm_protocol = 0;
+       rth->req.u.r.rt.rtm_scope = 0;
+       rth->req.u.r.rt.rtm_type = 0;
+       rth->req.u.r.rt.rtm_src_len = 0;
+       rth->req.u.r.rt.rtm_dst_len = rp->ai_addrlen << 3;
+       rth->req.u.r.rt.rtm_tos = 0;
+
+       __connman_inet_rtnl_addattr_l(&rth->req.n, sizeof(rth->req), RTA_DST,
+                               &rp->ai_addr, rp->ai_addrlen);
+
+       freeaddrinfo(rp);
+
+       err = __connman_inet_rtnl_open(rth);
+       if (err < 0)
+               goto fail;
+
+       data = g_try_malloc(sizeof(struct get_route_cb_data));
+       if (data == NULL) {
+               err = -ENOMEM;
+               goto done;
+       }
+
+       data->callback = callback;
+       data->user_data = user_data;
+
+#define GET_ROUTE_TIMEOUT 2
+       err = __connman_inet_rtnl_talk(rth, &rth->req.n, GET_ROUTE_TIMEOUT,
+                               get_route_cb, data);
+       if (err < 0) {
+               g_free(data);
+               goto done;
+       }
+
+       return 0;
+
+done:
+       __connman_inet_rtnl_close(rth);
+
+fail:
+       g_free(rth);
+       return err;
+}
+
 int connman_inet_check_ipaddress(const char *host)
 {
        struct addrinfo hints;