[PATCH net-next v2 4/4] ip6mr: add netlink notifications on mrt6msg cache reports

From: Julien Gomes
Date: Mon Jun 19 2017 - 16:44:40 EST


Add Netlink notifications on cache reports in ip6mr, in addition to the
existing mrt6msg sent to mroute6_sk.
Send RTM_NEWCACHEREPORT notifications to RTNLGRP_IPV6_MROUTE_R.

MSGTYPE, MIF_ID, SRC_ADDR and DST_ADDR Netlink attributes contain the
same data as their equivalent fields in the mrt6msg header.
PKT attribute is the packet sent to mroute6_sk, without the added
mrt6msg header.

Suggested-by: Ryan Halbrook <halbrook@xxxxxxxxxx>
Signed-off-by: Julien Gomes <julien@xxxxxxxxxx>
---
include/uapi/linux/mroute6.h | 12 ++++++++
net/ipv6/ip6mr.c | 67 ++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/mroute6.h b/include/uapi/linux/mroute6.h
index ed5721148768..e4746816c855 100644
--- a/include/uapi/linux/mroute6.h
+++ b/include/uapi/linux/mroute6.h
@@ -133,4 +133,16 @@ struct mrt6msg {
struct in6_addr im6_src, im6_dst;
};

+/* ip6mr netlink cache report attributes */
+enum {
+ IP6MRA_CREPORT_UNSPEC,
+ IP6MRA_CREPORT_MSGTYPE,
+ IP6MRA_CREPORT_MIF_ID,
+ IP6MRA_CREPORT_SRC_ADDR,
+ IP6MRA_CREPORT_DST_ADDR,
+ IP6MRA_CREPORT_PKT,
+ __IP6MRA_CREPORT_MAX
+};
+#define IP6MRA_CREPORT_MAX (__IP6MRA_CREPORT_MAX - 1)
+
#endif /* _UAPI__LINUX_MROUTE6_H */
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index b0e2bf1f4212..28a1fb49f12e 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -116,6 +116,7 @@ static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
struct mfc6_cache *c, struct rtmsg *rtm);
static void mr6_netlink_event(struct mr6_table *mrt, struct mfc6_cache *mfc,
int cmd);
+static void mrt6msg_netlink_event(struct mr6_table *mrt, struct sk_buff *pkt);
static int ip6mr_rtm_dumproute(struct sk_buff *skb,
struct netlink_callback *cb);
static void mroute_clean_tables(struct mr6_table *mrt, bool all);
@@ -1125,8 +1126,7 @@ static void ip6mr_cache_resolve(struct net *net, struct mr6_table *mrt,
}

/*
- * Bounce a cache query up to pim6sd. We could use netlink for this but pim6sd
- * expects the following bizarre scheme.
+ * Bounce a cache query up to pim6sd and netlink.
*
* Called under mrt_lock.
*/
@@ -1208,6 +1208,8 @@ static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,
return -EINVAL;
}

+ mrt6msg_netlink_event(mrt, skb);
+
/*
* Deliver to user space multicast routing algorithms
*/
@@ -2457,6 +2459,67 @@ static void mr6_netlink_event(struct mr6_table *mrt, struct mfc6_cache *mfc,
rtnl_set_sk_err(net, RTNLGRP_IPV6_MROUTE, err);
}

+static void mrt6msg_netlink_event(struct mr6_table *mrt, struct sk_buff *pkt)
+{
+ struct net *net = read_pnet(&mrt->net);
+ struct nlmsghdr *nlh;
+ struct rtgenmsg *rtgenm;
+ struct mrt6msg *msg;
+ struct sk_buff *skb;
+ struct nlattr *nla;
+ int payloadlen;
+ int msgsize;
+
+ payloadlen = pkt->len - sizeof(struct mrt6msg);
+ msg = (struct mrt6msg *)skb_transport_header(pkt);
+ msgsize = NLMSG_ALIGN(sizeof(struct rtgenmsg))
+ + nla_total_size(1)
+ /* IP6MRA_CREPORT_MSGTYPE */
+ + nla_total_size(2)
+ /* IP6MRA_CREPORT_MIF_ID */
+ + nla_total_size(sizeof(struct in6_addr))
+ /* IP6MRA_CREPORT_SRC_ADDR */
+ + nla_total_size(sizeof(struct in6_addr))
+ /* IP6MRA_CREPORT_DST_ADDR */
+ + nla_total_size(payloadlen)
+ /* IP6MRA_CREPORT_PKT */
+ ;
+
+ skb = nlmsg_new(msgsize, 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_IP6MR;
+ if (nla_put_u8(skb, IP6MRA_CREPORT_MSGTYPE, msg->im6_msgtype) ||
+ nla_put_u16(skb, IP6MRA_CREPORT_MIF_ID, msg->im6_mif) ||
+ nla_put_in6_addr(skb, IP6MRA_CREPORT_SRC_ADDR,
+ &msg->im6_src) ||
+ nla_put_in6_addr(skb, IP6MRA_CREPORT_DST_ADDR,
+ &msg->im6_dst))
+ goto nla_put_failure;
+
+ nla = nla_reserve(skb, IP6MRA_CREPORT_PKT, payloadlen);
+ if (!nla || skb_copy_bits(pkt, sizeof(struct mrt6msg),
+ nla_data(nla), payloadlen))
+ goto nla_put_failure;
+
+ nlmsg_end(skb, nlh);
+
+ rtnl_notify(skb, net, 0, RTNLGRP_IPV6_MROUTE_R, NULL, GFP_ATOMIC);
+ return;
+
+nla_put_failure:
+ nlmsg_cancel(skb, nlh);
+errout:
+ kfree_skb(skb);
+ rtnl_set_sk_err(net, RTNLGRP_IPV6_MROUTE_R, -ENOBUFS);
+}
+
static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
--
2.13.1