implement local ip access through policy routing

diff --git a/main.c b/main.c
index 407c8c2fb29b8a7f6956e37dd2230d8778840edf..8fbbed2e44804e723cc31277b9a689b97651725d 100644 (file)
--- a/main.c
+++ b/main.c
@@ -40,6 +40,9 @@ static int inet_sock;
 static int forward_bcast;
 static int forward_dhcp;
 
+uint8_t local_addr[4];
+int local_route_table;
+
 struct relayd_pending_route {
        struct relayd_route rt;
        struct uloop_timeout timeout;
@@ -641,6 +644,7 @@ static int usage(const char *progname)
                        "       -T <table>      Set routing table number for automatically added routes\n"
                        "       -B              Enable broadcast forwarding\n"
                        "       -D              Enable DHCP forwarding\n"
+                       "       -L <ipaddr>     Enable local access using <ipaddr> as source address\n"
                        "\n",
                progname);
        return -1;
@@ -650,6 +654,7 @@ int main(int argc, char **argv)
 {
        struct relayd_interface *rif = NULL;
        struct in_addr addr, addr2;
+       bool local_addr_valid = false;
        bool managed;
        int ifnum = 0;
        char *s, *s2;
@@ -665,9 +670,10 @@ int main(int argc, char **argv)
 
        host_timeout = 60;
        forward_bcast = 0;
+       local_route_table = 0;
        uloop_init();
 
-       while ((ch = getopt(argc, argv, "I:i:t:BDdT:G:R:")) != -1) {
+       while ((ch = getopt(argc, argv, "I:i:t:BDdT:G:R:L:")) != -1) {
                switch(ch) {
                case 'I':
                        managed = true;
@@ -706,6 +712,14 @@ int main(int argc, char **argv)
                        }
                        relayd_add_pending_route((uint8_t *) &addr.s_addr, (const uint8_t *) "\x00\x00\x00\x00", 0, 0);
                        break;
+               case 'L':
+                       if (!inet_aton(optarg, &addr)) {
+                               fprintf(stderr, "Address '%s' not found\n", optarg);
+                               return 1;
+                       }
+                       memcpy(&local_addr, &addr.s_addr, sizeof(local_addr));
+                       local_addr_valid = true;
+                       break;
                case 'R':
                        s = strchr(optarg, ':');
                        if (!s)
@@ -755,6 +769,9 @@ int main(int argc, char **argv)
        signal(SIGUSR1, die);
        signal(SIGUSR2, die);
 
+       if (local_addr_valid)
+               local_route_table = route_table++;
+
        if (relayd_rtnl_init() < 0)
                return 1;
 

diff --git a/relayd.h b/relayd.h
index e21ca08ca3890d8bcc48b0b3d65601635021b42d..cd24aa6feacd2f0199a8da8d2e8d6a2c8bd80307 100644 (file)
--- a/relayd.h
+++ b/relayd.h
@@ -100,6 +100,8 @@ struct rtnl_req {
 extern struct list_head interfaces;
 extern int debug;
 extern int route_table;
+extern uint8_t local_addr[4];
+extern int local_route_table;
 
 void rtnl_route_set(struct relayd_host *host, struct relayd_route *route, bool add);
 

diff --git a/route.c b/route.c
index abe026310dfff7d6064c9a85bb799114e7895902..cbb624e3eff6fdaf53f42fa16891573512532069 100644 (file)
--- a/route.c
+++ b/route.c
@@ -47,6 +47,14 @@ enum {
        RULE_F_DEFGW_WORKAROUND = (1 << 1),
 };
 
+static int get_route_table(struct relayd_interface *rif)
+{
+       if (rif)
+               return rif->rt_table;
+       else
+               return local_route_table;
+}
+
 static void
 rtnl_rule_request(struct relayd_interface *rif, int flags)
 {
@@ -73,21 +81,24 @@ rtnl_rule_request(struct relayd_interface *rif, int flags)
                        .rta_len = sizeof(req.table),
                },
        };
-
+       const char *ifname = "lo";
        int padding = sizeof(req.dev.ifname);
 
+       if (rif)
+               ifname = rif->ifname;
+
        if (!(flags & RULE_F_DEFGW_WORKAROUND)) {
                req.dev.rta.rta_type = FRA_IFNAME;
-               padding -= strlen(rif->ifname) + 1;
-               strcpy(req.dev.ifname, rif->ifname);
-               req.dev.rta.rta_len = sizeof(req.dev.rta) + strlen(rif->ifname) + 1;
+               padding -= strlen(ifname) + 1;
+               strcpy(req.dev.ifname, ifname);
+               req.dev.rta.rta_len = sizeof(req.dev.rta) + strlen(ifname) + 1;
        } else {
                req.dev.rta.rta_type = FRA_PRIORITY;
                req.dev.rta.rta_len = sizeof(req.dev.rta) + sizeof(uint32_t);
                padding -= sizeof(uint32_t);
                *((uint32_t *) &req.dev.ifname) = 1;
        }
-       req.table.table = rif->rt_table;
+       req.table.table = get_route_table(rif);
        req.nl.nlmsg_len = sizeof(req) - padding;
 
        req.nl.nlmsg_flags = NLM_F_REQUEST;
@@ -105,6 +116,19 @@ rtnl_rule_request(struct relayd_interface *rif, int flags)
        rtnl_flush();
 }
 
+struct rtnl_addr {
+       struct rtattr rta;
+       uint8_t ipaddr[4];
+} __packed;
+
+static struct rtnl_addr *
+rtnl_add_addr(struct rtnl_addr *addr, int *len, int type, const uint8_t *ipaddr)
+{
+       addr->rta.rta_type = type;
+       memcpy(addr->ipaddr, ipaddr, 4);
+       *len += sizeof(*addr);
+       return addr + 1;
+}
 
 static void
 rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host,
@@ -113,10 +137,6 @@ rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host,
        static struct {
                struct nlmsghdr nl;
                struct rtmsg rt;
-               struct {
-                       struct rtattr rta;
-                       uint8_t ipaddr[4];
-               } __packed dst;
                struct {
                        struct rtattr rta;
                        int table;
@@ -125,10 +145,7 @@ rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host,
                        struct rtattr rta;
                        int ifindex;
                } __packed dev;
-               struct {
-                       struct rtattr rta;
-                       uint8_t ipaddr[4];
-               } __packed gw;
+               struct rtnl_addr addr[3];
        } __packed req = {
                .rt = {
                        .rtm_family = AF_INET,
@@ -139,22 +156,20 @@ rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host,
                        .rta_type = RTA_TABLE,
                        .rta_len = sizeof(req.table),
                },
-               .dst.rta = {
-                       .rta_len = sizeof(req.dst),
-               },
                .dev.rta = {
                        .rta_type = RTA_OIF,
                        .rta_len = sizeof(req.dev),
                },
-               .gw.rta = {
-                       .rta_type = RTA_GATEWAY,
-                       .rta_len = sizeof(req.gw),
-               },
+               .addr[0].rta.rta_len = sizeof(struct rtnl_addr),
+               .addr[1].rta.rta_len = sizeof(struct rtnl_addr),
+               .addr[2].rta.rta_len = sizeof(struct rtnl_addr),
        };
-       int pktlen = sizeof(req);
+       int pktlen = sizeof(req) - sizeof(req.addr);
+       struct rtnl_addr *addr = &req.addr[0];
+       const char *ifname = "loopback";
 
        req.dev.ifindex = host->rif->sll.sll_ifindex;
-       req.table.table = rif->rt_table;
+       req.table.table = get_route_table(rif);
 
        req.nl.nlmsg_flags = NLM_F_REQUEST;
        if (add) {
@@ -173,27 +188,29 @@ rtnl_route_request(struct relayd_interface *rif, struct relayd_host *host,
                req.rt.rtm_scope = RT_SCOPE_NOWHERE;
        }
 
-       req.dst.rta.rta_type = RTA_DST;
+       if (rif)
+               ifname = rif->ifname;
+
        if (route) {
-               DPRINTF(2, "%s: add route to "IP_FMT"/%d via "IP_FMT"\n",
-                       host->rif->ifname, IP_BUF(route->dest), route->mask, IP_BUF(host->ipaddr));
-               if (!route->mask) {
-                       /* No DST -> reuse the DST attribute as the gateway attribute */
-                       memcpy(req.dst.ipaddr, host->ipaddr, sizeof(req.dst.ipaddr));
-                       req.dst.rta.rta_type = RTA_GATEWAY;
-                       pktlen -= sizeof(req.gw);
-                       req.rt.rtm_dst_len = 0;
-               } else {
-                       memcpy(req.gw.ipaddr, host->ipaddr, sizeof(req.gw.ipaddr));
-                       memcpy(req.dst.ipaddr, route->dest, sizeof(req.dst.ipaddr));
-                       req.rt.rtm_dst_len = route->mask;
-               }
+               DPRINTF(2, "%s: add route to "IP_FMT"/%d via "IP_FMT" (%s)\n", ifname,
+                       IP_BUF(route->dest), route->mask, IP_BUF(host->ipaddr),
+                       host->rif->ifname);
+
+               req.rt.rtm_dst_len = route->mask;
+               if (route->mask)
+                       addr = rtnl_add_addr(addr, &pktlen, RTA_DST, route->dest);
+               addr = rtnl_add_addr(addr, &pktlen, RTA_GATEWAY, host->ipaddr);
        } else {
-               pktlen -= sizeof(req.gw);
+               DPRINTF(2, "%s: add host route to "IP_FMT" (%s)\n", ifname,
+                       IP_BUF(host->ipaddr), host->rif->ifname);
+               addr = rtnl_add_addr(addr, &pktlen, RTA_DST, host->ipaddr);
                req.rt.rtm_dst_len = 32;
-               memcpy(req.dst.ipaddr, host->ipaddr, sizeof(req.dst.ipaddr));
        }
 
+       /* local route */
+       if (!rif)
+               addr = rtnl_add_addr(addr, &pktlen, RTA_PREFSRC, local_addr);
+
        req.nl.nlmsg_len = pktlen;
        if (route)
                rtnl_rule_request(rif, RULE_F_DEFGW_WORKAROUND | RULE_F_ADD);
@@ -214,6 +231,8 @@ rtnl_route_set(struct relayd_host *host, struct relayd_route *route, bool add)
 
                rtnl_route_request(rif, host, route, add);
        }
+       if (local_route_table)
+               rtnl_route_request(NULL, host, route, add);
 }
 
 void relayd_add_interface_routes(struct relayd_interface *rif)
@@ -372,12 +391,14 @@ int relayd_rtnl_init(void)
        rtnl_seq = time(NULL);
        rtnl_dump_seq = rtnl_seq;
        rtnl_dump_request(RTM_GETNEIGH);
+       rtnl_rule_request(NULL, RULE_F_ADD);
 
        return 0;
 }
 
 void relayd_rtnl_done(void)
 {
+       rtnl_rule_request(NULL, 0);
        uloop_fd_delete(&rtnl_sock);
        close(rtnl_sock.fd);
 }