ipv6: ip6mr: add support for dumping routing tables over netlink

The ip6mr /proc interface (ip6_mr_cache) can't be extended to dump routes
from any tables but the main table in a backwards compatible fashion since
the output format ends in a variable amount of output interfaces.

Introduce a new netlink interface to dump multicast routes from all tables,
similar to the netlink interface for regular routes.

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index c2920a1a6db38732fff6be3690aae2c9fe64cf0d..163850e22b111c2d69df1316c0c4090c44a828bf 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -112,8 +112,10 @@ static int ip6_mr_forward(struct net *net, struct mr6_table *mrt,
                          struct sk_buff *skb, struct mfc6_cache *cache);
 static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,
                              mifi_t mifi, int assert);
-static int ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
-                            struct mfc6_cache *c, struct rtmsg *rtm);
+static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
+                              struct mfc6_cache *c, struct rtmsg *rtm);
+static int ip6mr_rtm_dumproute(struct sk_buff *skb,
+                              struct netlink_callback *cb);
 static void mroute_clean_tables(struct mr6_table *mrt);
 static void ipmr_expire_process(unsigned long arg);
 
@@ -1038,7 +1040,7 @@ static void ip6mr_cache_resolve(struct net *net, struct mr6_table *mrt,
                        int err;
                        struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct ipv6hdr));
 
-                       if (ip6mr_fill_mroute(mrt, skb, c, NLMSG_DATA(nlh)) > 0) {
+                       if (__ip6mr_fill_mroute(mrt, skb, c, NLMSG_DATA(nlh)) > 0) {
                                nlh->nlmsg_len = skb_tail_pointer(skb) - (u8 *)nlh;
                        } else {
                                nlh->nlmsg_type = NLMSG_ERROR;
@@ -1350,6 +1352,7 @@ int __init ip6_mr_init(void)
                goto add_proto_fail;
        }
 #endif
+       rtnl_register(RTNL_FAMILY_IP6MR, RTM_GETROUTE, NULL, ip6mr_rtm_dumproute);
        return 0;
 #ifdef CONFIG_IPV6_PIMSM_V2
 add_proto_fail:
@@ -2007,9 +2010,8 @@ int ip6_mr_input(struct sk_buff *skb)
 }
 
 
-static int
-ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
-                 struct mfc6_cache *c, struct rtmsg *rtm)
+static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
+                              struct mfc6_cache *c, struct rtmsg *rtm)
 {
        int ct;
        struct rtnexthop *nhp;
@@ -2111,8 +2113,88 @@ int ip6mr_get_route(struct net *net,
        if (!nowait && (rtm->rtm_flags&RTM_F_NOTIFY))
                cache->mfc_flags |= MFC_NOTIFY;
 
-       err = ip6mr_fill_mroute(mrt, skb, cache, rtm);
+       err = __ip6mr_fill_mroute(mrt, skb, cache, rtm);
        read_unlock(&mrt_lock);
        return err;
 }
 
+static int ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
+                            u32 pid, u32 seq, struct mfc6_cache *c)
+{
+       struct nlmsghdr *nlh;
+       struct rtmsg *rtm;
+
+       nlh = nlmsg_put(skb, pid, seq, RTM_NEWROUTE, sizeof(*rtm), NLM_F_MULTI);
+       if (nlh == NULL)
+               return -EMSGSIZE;
+
+       rtm = nlmsg_data(nlh);
+       rtm->rtm_family   = RTNL_FAMILY_IPMR;
+       rtm->rtm_dst_len  = 128;
+       rtm->rtm_src_len  = 128;
+       rtm->rtm_tos      = 0;
+       rtm->rtm_table    = mrt->id;
+       NLA_PUT_U32(skb, RTA_TABLE, mrt->id);
+       rtm->rtm_scope    = RT_SCOPE_UNIVERSE;
+       rtm->rtm_protocol = RTPROT_UNSPEC;
+       rtm->rtm_flags    = 0;
+
+       NLA_PUT(skb, RTA_SRC, 16, &c->mf6c_origin);
+       NLA_PUT(skb, RTA_DST, 16, &c->mf6c_mcastgrp);
+
+       if (__ip6mr_fill_mroute(mrt, skb, c, rtm) < 0)
+               goto nla_put_failure;
+
+       return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+       nlmsg_cancel(skb, nlh);
+       return -EMSGSIZE;
+}
+
+static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       struct net *net = sock_net(skb->sk);
+       struct mr6_table *mrt;
+       struct mfc6_cache *mfc;
+       unsigned int t = 0, s_t;
+       unsigned int h = 0, s_h;
+       unsigned int e = 0, s_e;
+
+       s_t = cb->args[0];
+       s_h = cb->args[1];
+       s_e = cb->args[2];
+
+       read_lock(&mrt_lock);
+       ip6mr_for_each_table(mrt, net) {
+               if (t < s_t)
+                       goto next_table;
+               if (t > s_t)
+                       s_h = 0;
+               for (h = s_h; h < MFC6_LINES; h++) {
+                       list_for_each_entry(mfc, &mrt->mfc6_cache_array[h], list) {
+                               if (e < s_e)
+                                       goto next_entry;
+                               if (ip6mr_fill_mroute(mrt, skb,
+                                                     NETLINK_CB(cb->skb).pid,
+                                                     cb->nlh->nlmsg_seq,
+                                                     mfc) < 0)
+                                       goto done;
+next_entry:
+                               e++;
+                       }
+                       e = s_e = 0;
+               }
+               s_h = 0;
+next_table:
+               t++;
+       }
+done:
+       read_unlock(&mrt_lock);
+
+       cb->args[2] = e;
+       cb->args[1] = h;
+       cb->args[0] = t;
+
+       return skb->len;
+}