ipmr: add netlink notifications on igmpmsg cache reports

Add Netlink notifications on cache reports in ipmr, in addition to the
existing igmpmsg sent to mroute_sk.
Send RTM_NEWCACHEREPORT notifications to RTNLGRP_IPV4_MROUTE_R.

MSGTYPE, VIF_ID, SRC_ADDR and DST_ADDR Netlink attributes contain the
same data as their equivalent fields in the igmpmsg header.
PKT attribute is the packet sent to mroute_sk, without the added igmpmsg
header.

Suggested-by: Ryan Halbrook <halbrook@arista.com>
Signed-off-by: Julien Gomes <julien@arista.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/mroute.h b/include/uapi/linux/mroute.h
index f904367c0ceef610d5ce9a78fea180bd4753a2f1..e8e5041dea8e04ddb66851924f0dd3ecfd61c49e 100644 (file)
--- a/include/uapi/linux/mroute.h
+++ b/include/uapi/linux/mroute.h
@@ -152,6 +152,18 @@ enum {
 };
 #define IPMRA_VIFA_MAX (__IPMRA_VIFA_MAX - 1)
 
+/* ipmr netlink cache report attributes */
+enum {
+       IPMRA_CREPORT_UNSPEC,
+       IPMRA_CREPORT_MSGTYPE,
+       IPMRA_CREPORT_VIF_ID,
+       IPMRA_CREPORT_SRC_ADDR,
+       IPMRA_CREPORT_DST_ADDR,
+       IPMRA_CREPORT_PKT,
+       __IPMRA_CREPORT_MAX
+};
+#define IPMRA_CREPORT_MAX (__IPMRA_CREPORT_MAX - 1)
+
 /* That's all usermode folks */
 
 #define MFC_ASSERT_THRESH (3*HZ)               /* Maximal freq. of asserts */

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 3e7454aa49e87f49364b1d61c0f300af467e851a..a1d521be612bd6d2bd92c64dbb32fefd80881470 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -109,6 +109,7 @@ static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
                              struct mfc_cache *c, struct rtmsg *rtm);
 static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
                                 int cmd);
+static void igmpmsg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt);
 static void mroute_clean_tables(struct mr_table *mrt, bool all);
 static void ipmr_expire_process(unsigned long arg);
 
@@ -995,8 +996,7 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
        }
 }
 
-/* Bounce a cache query up to mrouted. We could use netlink for this but mrouted
- * expects the following bizarre scheme.
+/* Bounce a cache query up to mrouted and netlink.
  *
  * Called under mrt_lock.
  */
@@ -1062,6 +1062,8 @@ static int ipmr_cache_report(struct mr_table *mrt,
                return -EINVAL;
        }
 
+       igmpmsg_netlink_event(mrt, skb);
+
        /* Deliver to mrouted */
        ret = sock_queue_rcv_skb(mroute_sk, skb);
        rcu_read_unlock();
@@ -2341,6 +2343,69 @@ errout:
                rtnl_set_sk_err(net, RTNLGRP_IPV4_MROUTE, err);
 }
 
+static size_t igmpmsg_netlink_msgsize(size_t payloadlen)
+{
+       size_t len =
+               NLMSG_ALIGN(sizeof(struct rtgenmsg))
+               + nla_total_size(1)     /* IPMRA_CREPORT_MSGTYPE */
+               + nla_total_size(4)     /* IPMRA_CREPORT_VIF_ID */
+               + nla_total_size(4)     /* IPMRA_CREPORT_SRC_ADDR */
+               + nla_total_size(4)     /* IPMRA_CREPORT_DST_ADDR */
+                                       /* IPMRA_CREPORT_PKT */
+               + nla_total_size(payloadlen)
+               ;
+
+       return len;
+}
+
+static void igmpmsg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt)
+{
+       struct net *net = read_pnet(&mrt->net);
+       struct nlmsghdr *nlh;
+       struct rtgenmsg *rtgenm;
+       struct igmpmsg *msg;
+       struct sk_buff *skb;
+       struct nlattr *nla;
+       int payloadlen;
+
+       payloadlen = pkt->len - sizeof(struct igmpmsg);
+       msg = (struct igmpmsg *)skb_network_header(pkt);
+
+       skb = nlmsg_new(igmpmsg_netlink_msgsize(payloadlen), GFP_ATOMIC);
+       if (!skb)
+               goto errout;
+
+       nlh = nlmsg_put(skb, 0, 0, RTM_NEWCACHEREPORT,
+                       sizeof(struct rtgenmsg), 0);
+       if (!nlh)
+               goto errout;
+       rtgenm = nlmsg_data(nlh);
+       rtgenm->rtgen_family = RTNL_FAMILY_IPMR;
+       if (nla_put_u8(skb, IPMRA_CREPORT_MSGTYPE, msg->im_msgtype) ||
+           nla_put_u32(skb, IPMRA_CREPORT_VIF_ID, msg->im_vif) ||
+           nla_put_in_addr(skb, IPMRA_CREPORT_SRC_ADDR,
+                           msg->im_src.s_addr) ||
+           nla_put_in_addr(skb, IPMRA_CREPORT_DST_ADDR,
+                           msg->im_dst.s_addr))
+               goto nla_put_failure;
+
+       nla = nla_reserve(skb, IPMRA_CREPORT_PKT, payloadlen);
+       if (!nla || skb_copy_bits(pkt, sizeof(struct igmpmsg),
+                                 nla_data(nla), payloadlen))
+               goto nla_put_failure;
+
+       nlmsg_end(skb, nlh);
+
+       rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MROUTE_R, NULL, GFP_ATOMIC);
+       return;
+
+nla_put_failure:
+       nlmsg_cancel(skb, nlh);
+errout:
+       kfree_skb(skb);
+       rtnl_set_sk_err(net, RTNLGRP_IPV4_MROUTE_R, -ENOBUFS);
+}
+
 static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
 {
        struct net *net = sock_net(skb->sk);