.gateway configuration

This directive adds a default route to the guest at startup.

syntax:
	lxc.network.ipv4.gateway = 10.0.0.1
	lxc.network.ipv6.gateway = 2001:db8:85a3::8a2e:370:7334

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 2eb598bc6b4511a91b2122beb54db27a7c12491f..751dce04d56900da137021adf49d2a840fcfbcc5 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1321,6 +1321,51 @@ static int setup_netdev(struct lxc_netdev *netdev)
                }
        }
 
+       /* We can only set up the default routes after bringing
+        * up the interface, sine bringing up the interface adds
+        * the link-local routes and we can't add a default
+        * route if the gateway is not reachable. */
+
+       /* setup ipv4 gateway on the interface */
+       if (netdev->ipv4_gateway) {
+               if (!(netdev->flags & IFF_UP)) {
+                       ERROR("Cannot add ipv4 gateway for %s when not bringing up the interface", ifname);
+                       return -1;
+               }
+
+               if (lxc_list_empty(&netdev->ipv4)) {
+                       ERROR("Cannot add ipv4 gateway for %s when not assigning an address", ifname);
+                       return -1;
+               }
+
+               err = lxc_ipv4_gateway_add(netdev->ifindex, netdev->ipv4_gateway);
+               if (err) {
+                       ERROR("failed to setup ipv4 gateway for '%s': %s",
+                                     ifname, strerror(-err));
+                       return -1;
+               }
+       }
+
+       /* setup ipv6 gateway on the interface */
+       if (netdev->ipv6_gateway) {
+               if (!(netdev->flags & IFF_UP)) {
+                       ERROR("Cannot add ipv6 gateway for %s when not bringing up the interface", ifname);
+                       return -1;
+               }
+
+               if (lxc_list_empty(&netdev->ipv6) && !IN6_IS_ADDR_LINKLOCAL(netdev->ipv6_gateway)) {
+                       ERROR("Cannot add ipv6 gateway for %s when not assigning an address", ifname);
+                       return -1;
+               }
+
+               err = lxc_ipv6_gateway_add(netdev->ifindex, netdev->ipv6_gateway);
+               if (err) {
+                       ERROR("failed to setup ipv6 gateway for '%s': %s",
+                                     ifname, strerror(-err));
+                       return -1;
+               }
+       }
+
        DEBUG("'%s' has been setup", current_ifname);
 
        return 0;

diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index 8fd3dd8c1f1d46cad7d5a11584162f7402762f70..328d236dec69ff783fab4451101b15a6d07d9424 100644 (file)
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -114,6 +114,8 @@ struct lxc_netdev {
        union netdev_p priv;
        struct lxc_list ipv4;
        struct lxc_list ipv6;
+       struct in_addr *ipv4_gateway;
+       struct in6_addr *ipv6_gateway;
        char *upscript;
 };
 

diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 8d8d8e575b2c4eb50e54ab4c95c015308e9cc429..8e215f80746529629600a12905e3bbcb6f699020 100644 (file)
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -63,8 +63,10 @@ static int config_network_hwaddr(const char *, char *, struct lxc_conf *);
 static int config_network_vlan_id(const char *, char *, struct lxc_conf *);
 static int config_network_mtu(const char *, char *, struct lxc_conf *);
 static int config_network_ipv4(const char *, char *, struct lxc_conf *);
+static int config_network_ipv4_gateway(const char *, char *, struct lxc_conf *);
 static int config_network_script(const char *, char *, struct lxc_conf *);
 static int config_network_ipv6(const char *, char *, struct lxc_conf *);
+static int config_network_ipv6_gateway(const char *, char *, struct lxc_conf *);
 static int config_cap_drop(const char *, char *, struct lxc_conf *);
 static int config_console(const char *, char *, struct lxc_conf *);
 
@@ -96,7 +98,9 @@ static struct config config[] = {
        { "lxc.network.hwaddr",       config_network_hwaddr       },
        { "lxc.network.mtu",          config_network_mtu          },
        { "lxc.network.vlan.id",      config_network_vlan_id      },
+       { "lxc.network.ipv4.gateway", config_network_ipv4_gateway },
        { "lxc.network.ipv4",         config_network_ipv4         },
+       { "lxc.network.ipv6.gateway", config_network_ipv6_gateway },
        { "lxc.network.ipv6",         config_network_ipv6         },
        { "lxc.cap.drop",             config_cap_drop             },
        { "lxc.console",              config_console              },
@@ -433,6 +437,37 @@ static int config_network_ipv4(const char *key, char *value,
        return 0;
 }
 
+static int config_network_ipv4_gateway(const char *key, char *value,
+                                      struct lxc_conf *lxc_conf)
+{
+       struct lxc_netdev *netdev;
+       struct in_addr *gw;
+
+       netdev = network_netdev(key, value, &lxc_conf->network);
+       if (!netdev)
+               return -1;
+
+       gw = malloc(sizeof(*gw));
+       if (!gw) {
+               SYSERROR("failed to allocate ipv4 gateway address");
+               return -1;
+       }
+
+       if (!value) {
+               ERROR("no ipv4 gateway address specified");
+               return -1;
+       }
+
+       if (!inet_pton(AF_INET, value, gw)) {
+               SYSERROR("invalid ipv4 gateway address: %s", value);
+               return -1;
+       }
+
+       netdev->ipv4_gateway = gw;
+
+       return 0;
+}
+
 static int config_network_ipv6(const char *key, char *value,
                               struct lxc_conf *lxc_conf)
 {
@@ -480,6 +515,37 @@ static int config_network_ipv6(const char *key, char *value,
        return 0;
 }
 
+static int config_network_ipv6_gateway(const char *key, char *value,
+                                      struct lxc_conf *lxc_conf)
+{
+       struct lxc_netdev *netdev;
+       struct in6_addr *gw;
+
+       netdev = network_netdev(key, value, &lxc_conf->network);
+       if (!netdev)
+               return -1;
+
+       gw = malloc(sizeof(*gw));
+       if (!gw) {
+               SYSERROR("failed to allocate ipv6 gateway address");
+               return -1;
+       }
+
+       if (!value) {
+               ERROR("no ipv6 gateway address specified");
+               return -1;
+       }
+
+       if (!inet_pton(AF_INET6, value, gw)) {
+               SYSERROR("invalid ipv6 gateway address: %s", value);
+               return -1;
+       }
+
+       netdev->ipv6_gateway = gw;
+
+       return 0;
+}
+
 static int config_network_script(const char *key, char *value,
                                 struct lxc_conf *lxc_conf)
 {

diff --git a/src/lxc/network.c b/src/lxc/network.c
index 420117a070d7cd302bd6f6640f46dfbc0f568787..b1d60f2bbc2817a11ca3b86f6c2a74ac4bf6f31f 100644 (file)
--- a/src/lxc/network.c
+++ b/src/lxc/network.c
@@ -89,6 +89,11 @@ struct ip_req {
        struct ifaddrmsg ifa;
 };
 
+struct rt_req {
+       struct nlmsg nlmsg;
+       struct rtmsg rt;
+};
+
 int lxc_netdev_move_by_index(int ifindex, pid_t pid)
 {
        struct nl_handler nlh;
@@ -741,6 +746,71 @@ int lxc_ipv4_addr_add(int ifindex, struct in_addr *addr,
        return ip_addr_add(AF_INET, ifindex, addr, bcast, NULL, prefix);
 }
 
+static int ip_gateway_add(int family, int ifindex, void *gw)
+{
+       struct nl_handler nlh;
+       struct nlmsg *nlmsg = NULL, *answer = NULL;
+       struct rt_req *rt_req;
+       int addrlen;
+       int err;
+
+       addrlen = family == AF_INET ? sizeof(struct in_addr) :
+               sizeof(struct in6_addr);
+
+       err = netlink_open(&nlh, NETLINK_ROUTE);
+       if (err)
+               return err;
+
+       err = -ENOMEM;
+       nlmsg = nlmsg_alloc(NLMSG_GOOD_SIZE);
+       if (!nlmsg)
+               goto out;
+
+       answer = nlmsg_alloc(NLMSG_GOOD_SIZE);
+       if (!answer)
+               goto out;
+
+       rt_req = (struct rt_req *)nlmsg;
+       rt_req->nlmsg.nlmsghdr.nlmsg_len =
+               NLMSG_LENGTH(sizeof(struct rtmsg));
+       rt_req->nlmsg.nlmsghdr.nlmsg_flags =
+               NLM_F_ACK|NLM_F_REQUEST|NLM_F_CREATE|NLM_F_EXCL;
+       rt_req->nlmsg.nlmsghdr.nlmsg_type = RTM_NEWROUTE;
+       rt_req->rt.rtm_family = family;
+       rt_req->rt.rtm_table = RT_TABLE_MAIN;
+       rt_req->rt.rtm_scope = RT_SCOPE_UNIVERSE;
+       rt_req->rt.rtm_protocol = RTPROT_BOOT;
+       rt_req->rt.rtm_type = RTN_UNICAST;
+       /* "default" destination */
+       rt_req->rt.rtm_dst_len = 0;
+
+       err = -EINVAL;
+       if (nla_put_buffer(nlmsg, RTA_GATEWAY, gw, addrlen))
+               goto out;
+
+       /* Adding the interface index enables the use of link-local
+        * addresses for the gateway */
+       if (nla_put_u32(nlmsg, RTA_OIF, ifindex))
+               goto out;
+
+       err = netlink_transaction(&nlh, nlmsg, answer);
+out:
+       netlink_close(&nlh);
+       nlmsg_free(answer);
+       nlmsg_free(nlmsg);
+       return err;
+}
+
+int lxc_ipv4_gateway_add(int ifindex, struct in_addr *gw)
+{
+       return ip_gateway_add(AF_INET, ifindex, gw);
+}
+
+int lxc_ipv6_gateway_add(int ifindex, struct in6_addr *gw)
+{
+       return ip_gateway_add(AF_INET6, ifindex, gw);
+}
+
 /*
  * There is a lxc_bridge_attach, but no need of a bridge detach
  * as automatically done by kernel when a netdev is deleted.

diff --git a/src/lxc/network.h b/src/lxc/network.h
index 0d6eb4c92134c2b5346ace43ceafea960ed77db4..5a1fd50ca71a9a76c575a4d89e0adb026ecda7db 100644 (file)
--- a/src/lxc/network.h
+++ b/src/lxc/network.h
@@ -83,6 +83,12 @@ extern int lxc_ipv6_addr_add(int ifindex, struct in6_addr *addr,
 extern int lxc_ipv4_addr_add(int ifindex, struct in_addr *addr,
                             struct in_addr *bcast, int prefix);
 
+/*
+ * Set default route.
+ */
+extern int lxc_ipv4_gateway_add(int ifindex, struct in_addr *gw);
+extern int lxc_ipv6_gateway_add(int ifindex, struct in6_addr *gw);
+
 /*
  * Attach an interface to the bridge
  */