Re: [PATCH net-next v3 4/4] ip6mr: add netlink notifications on mrt6msg cache reports

[Nikolay Aleksandrov]

On 20/06/17 23:54, Julien Gomes wrote:
> 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 
> Signed-off-by: Julien Gomes 
> ---
>  include/uapi/linux/mroute6.h | 12 
>  net/ipv6/ip6mr.c | 71 
> ++--
>  2 files changed, 81 insertions(+), 2 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov 

[PATCH net-next v3 4/4] ip6mr: add netlink notifications on mrt6msg cache reports

[Julien Gomes]

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 
Signed-off-by: Julien Gomes 
---
 include/uapi/linux/mroute6.h | 12 
 net/ipv6/ip6mr.c | 71 ++--
 2 files changed, 81 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..7454850f2098 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 +2459,71 @@ static void mr6_netlink_event(struct mr6_table *mrt, 
struct mfc6_cache *mfc,
rtnl_set_sk_err(net, RTNLGRP_IPV6_MROUTE, err);
 }
 
+static size_t mrt6msg_netlink_msgsize(size_t payloadlen)
+{
+   size_t len =
+   NLMSG_ALIGN(sizeof(struct rtgenmsg))
+   + nla_total_size(1) /* IP6MRA_CREPORT_MSGTYPE */
+   + nla_total_size(4) /* IP6MRA_CREPORT_MIF_ID */
+   /* IP6MRA_CREPORT_SRC_ADDR */
+   + nla_total_size(sizeof(struct in6_addr))
+   /* IP6MRA_CREPORT_DST_ADDR */
+   + nla_total_size(sizeof(struct in6_addr))
+   /* IP6MRA_CREPORT_PKT */
+   + nla_total_size(payloadlen)
+   ;
+
+   return len;
+}
+
+static void mrt6msg_netlink_event(struct mr6_table *mrt, struct sk_buff *pkt)
+{
+   struct net *net = read_pnet(>net);
+   struct nlmsghdr *nlh;
+   struct rtgenmsg *rtgenm;
+   struct mrt6msg *msg;
+   struct sk_buff *skb;
+   struct nlattr *nla;
+   int payloadlen;
+
+   payloadlen = pkt->len - sizeof(struct mrt6msg);
+   msg = (struct mrt6msg *)skb_transport_header(pkt);
+
+   skb = nlmsg_new(mrt6msg_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_IP6MR;
+   if (nla_put_u8(skb, IP6MRA_CREPORT_MSGTYPE, msg->im6_msgtype) ||
+   nla_put_u32(skb, IP6MRA_CREPORT_MIF_ID, msg->im6_mif) ||
+   nla_put_in6_addr(skb, IP6MRA_CREPORT_SRC_ADDR,
+>im6_src) ||
+   nla_put_in6_addr(skb, IP6MRA_CREPORT_DST_ADDR,
+>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:
+