linux: Use the VRF link routing table in non manager

dhcpcd is limited it only one routing table and better VRF support
would need more extensive changes.
We detect the VRF table for the specificed interface when dhcpcd
initially creates routes and we use that table for lifetime of
the dhcpcd process.

Should address #238

diff --git a/src/if-linux.c b/src/if-linux.c
index cb3895360856173bc20dde71337b641fdd526fc6..59840e5885d6e9a893b208809efbf3a5d0d24c24 100644 (file)
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -273,6 +273,22 @@ check_proc_uint(struct dhcpcd_ctx *ctx, const char *path, unsigned int *u)
        return 0;
 }
 
+static int
+parse_rtattr(struct rtattr *tb[], size_t max, struct rtattr *rta, size_t len)
+{
+       unsigned short type;
+
+       memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+       for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+               type = (unsigned short)(rta->rta_type & NLA_TYPE_MASK);
+               if (type <= max && !tb[type])
+                       tb[type] = rta;
+       }
+       return 0;
+}
+#define parse_rtattr_nested(tb, max, rta) \
+       (parse_rtattr((tb), (max), RTA_DATA(rta), RTA_PAYLOAD(rta)))
+
 static ssize_t
 if_writepathuint(struct dhcpcd_ctx *ctx, const char *path, unsigned int val)
 {
@@ -645,6 +661,7 @@ recv_again:
 static int
 if_copyrt(struct dhcpcd_ctx *ctx, struct rt *rt, struct nlmsghdr *nlm)
 {
+       struct priv *priv = ctx->priv;
        size_t len;
        struct rtmsg *rtm;
        struct rtattr *rta;
@@ -657,7 +674,7 @@ if_copyrt(struct dhcpcd_ctx *ctx, struct rt *rt, struct nlmsghdr *nlm)
                return -1;
        }
        rtm = (struct rtmsg *)NLMSG_DATA(nlm);
-       if (rtm->rtm_table != RT_TABLE_MAIN)
+       if (rtm->rtm_table != priv->rt_table)
                return -1;
 
        memset(rt, 0, sizeof(*rt));
@@ -1491,6 +1508,13 @@ struct nlma
        char buffer[64];
 };
 
+struct nlmi
+{
+       struct nlmsghdr hdr;
+       struct ifinfomsg ifi;
+       char buffer[1024];
+};
+
 #ifdef INET
 struct ifiaddr
 {
@@ -1560,9 +1584,74 @@ struct nlmr
        char buffer[256];
 };
 
+#ifdef IFLA_VRF_MAX
+static int
+_if_vrf_table(__unused struct dhcpcd_ctx *ctx,
+    void *arg, struct nlmsghdr *nlm)
+{
+       uint32_t *table = arg;
+       struct ifinfomsg *ifi;
+       size_t len;
+
+       struct rtattr *tb[IFLA_MAX + 1];
+       struct rtattr *li[IFLA_INFO_MAX + 1];
+       struct rtattr *vrf[IFLA_VRF_MAX + 1];
+
+       // Default to unspecified table
+       *table = 0;
+
+       ifi = NLMSG_DATA(nlm);
+       len = NLMSG_PAYLOAD(nlm, sizeof(*ifi));
+
+       parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
+       if (!tb[IFLA_LINKINFO])
+               return 0;
+
+       parse_rtattr_nested(li, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
+
+       if (!li[IFLA_INFO_KIND] || strcmp(RTA_DATA(li[IFLA_INFO_KIND]), "vrf"))
+               return 0;
+
+       if (!li[IFLA_INFO_DATA])
+               return 0;
+
+       parse_rtattr_nested(vrf, IFLA_VRF_MAX, li[IFLA_INFO_DATA]);
+       if (vrf[IFLA_VRF_TABLE])
+               *table = *(uint32_t *)RTA_DATA(vrf[IFLA_VRF_TABLE]);
+
+       return 0;
+}
+
+static unsigned char
+if_vrf_table(const struct interface *ifp)
+{
+       uint32_t table;
+       struct nlmi nlm = {
+           .hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+           .hdr.nlmsg_type = RTM_GETLINK,
+           .hdr.nlmsg_flags = NLM_F_REQUEST,
+           .ifi.ifi_family = AF_UNSPEC,
+       };
+
+       add_attr_l(&nlm.hdr, sizeof(nlm), IFLA_IFNAME,
+           ifp->name, (unsigned short)(strlen(ifp->name) + 1));
+
+       int error = if_sendnetlink(ifp->ctx, NETLINK_ROUTE, &nlm.hdr,
+           &_if_vrf_table, &table);
+       if (error == -1) {
+               logerr(__func__);
+               return 0;
+       }
+       return (unsigned char)table;
+}
+#else
+#define        if_vrf_table(ifp)       0
+#endif
+
 int
 if_route(unsigned char cmd, const struct rt *rt)
 {
+       struct priv *priv = rt->rt_ifp->ctx->priv;
        struct nlmr nlm;
        bool gateway_unspec;
 
@@ -1583,7 +1672,7 @@ if_route(unsigned char cmd, const struct rt *rt)
        }
        nlm.hdr.nlmsg_flags |= NLM_F_REQUEST;
        nlm.rt.rtm_family = (unsigned char)rt->rt_dest.sa_family;
-       nlm.rt.rtm_table = RT_TABLE_MAIN;
+       nlm.rt.rtm_table = priv->rt_table;
 
        gateway_unspec = sa_is_unspecified(&rt->rt_gateway);
 
@@ -1707,11 +1796,34 @@ _if_initrt(struct dhcpcd_ctx *ctx, void *arg,
 int
 if_initrt(struct dhcpcd_ctx *ctx, rb_tree_t *kroutes, int af)
 {
+       struct priv *priv = ctx->priv;
+
+#ifdef IFLA_VRF_MAX
+       if (!priv->rt_table) {
+               /* dhcpcd routing only works on one table.
+                * For VRF we can work it out. */
+               struct interface *ifp;
+
+               if (!(ctx->options & DHCPCD_MANAGER)) {
+                       if (!priv->rt_table) {
+                               TAILQ_FOREACH(ifp, ctx->ifaces, next) {
+                                       if (ifp->active == IF_ACTIVE_USER)
+                                               break;
+                               }
+                               if (ifp)
+                                       priv->rt_table = if_vrf_table(ifp);
+                       }
+               }
+       }
+#endif
+       if (!priv->rt_table)
+               priv->rt_table = RT_TABLE_MAIN;
+
        struct nlmr nlm = {
            .hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)),
            .hdr.nlmsg_type = RTM_GETROUTE,
            .hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_MATCH,
-           .rt.rtm_table = RT_TABLE_MAIN,
+           .rt.rtm_table = priv->rt_table,
            .rt.rtm_family = (unsigned char)af,
        };
 

diff --git a/src/if.h b/src/if.h
index df5f921e63987562c2f3ba0268940d8a2ac21dab..2f614a23aa4aad808f046d82a122326d50e500d3 100644 (file)
--- a/src/if.h
+++ b/src/if.h
@@ -137,6 +137,7 @@ struct priv {
        int route_fd;
        int generic_fd;
        uint32_t route_pid;
+       unsigned char rt_table;
 };
 #endif
 #ifdef __sun