From 8a259b208fcccf5bab30a27e6b9130161a495e85 Mon Sep 17 00:00:00 2001 From: Yuyang Huang Date: Wed, 11 Dec 2024 17:22:41 +0900 Subject: [PATCH] netlink: add IGMP/MLD join/leave notifications MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This change introduces netlink notifications for multicast address changes. The following features are included: * Addition and deletion of multicast addresses are reported using RTM_NEWMULTICAST and RTM_DELMULTICAST messages with AF_INET and AF_INET6. * Two new notification groups: RTNLGRP_IPV4_MCADDR and RTNLGRP_IPV6_MCADDR are introduced for receiving these events. This change allows user space applications (e.g., ip monitor) to efficiently track multicast group memberships by listening for netlink events. Previously, applications relied on inefficient polling of procfs, introducing delays. With netlink notifications, applications receive realtime updates on multicast group membership changes, enabling more precise metrics collection and system monitoring.  This change also unlocks the potential for implementing a wide range of sophisticated multicast related features in user space by allowing applications to combine kernel provided multicast address information with user space data and communicate decisions back to the kernel for more fine grained control. This mechanism can be used for various purposes, including multicast filtering, IGMP/MLD offload, and IGMP/MLD snooping. Cc: Maciej Żenczykowski Cc: Lorenzo Colitti Co-developed-by: Patrick Ruddy Signed-off-by: Patrick Ruddy Link: https://lore.kernel.org/r/20180906091056.21109-1-pruddy@vyatta.att-mail.com Signed-off-by: Yuyang Huang Signed-off-by: NipaLocal --- include/linux/igmp.h | 2 ++ include/net/addrconf.h | 21 +++++++++++ include/uapi/linux/rtnetlink.h | 10 +++++- net/ipv4/igmp.c | 64 ++++++++++++++++++++++++++++++++++ net/ipv6/addrconf.c | 29 +++++---------- net/ipv6/mcast.c | 39 +++++++++++++++++++++ 6 files changed, 144 insertions(+), 21 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 5171231f70a8b3..073b30a9b8508f 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -87,6 +87,8 @@ struct ip_mc_list { char loaded; unsigned char gsquery; /* check source marks? */ unsigned char crcount; + unsigned long mca_cstamp; + unsigned long mca_tstamp; struct rcu_head rcu; }; diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 363dd63babe72f..58337898fa21d5 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -88,6 +88,23 @@ struct ifa6_config { u16 scope; }; +enum addr_type_t { + UNICAST_ADDR, + MULTICAST_ADDR, + ANYCAST_ADDR, +}; + +struct inet6_fill_args { + u32 portid; + u32 seq; + int event; + unsigned int flags; + int netnsid; + int ifindex; + enum addr_type_t type; + bool force_rt_scope_universe; +}; + int addrconf_init(void); void addrconf_cleanup(void); @@ -525,4 +542,8 @@ int if6_proc_init(void); void if6_proc_exit(void); #endif +int inet6_fill_ifmcaddr(struct sk_buff *skb, + const struct ifmcaddr6 *ifmca, + struct inet6_fill_args *args); + #endif diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h index db7254d52d9355..eccc0e7dcb7dbc 100644 --- a/include/uapi/linux/rtnetlink.h +++ b/include/uapi/linux/rtnetlink.h @@ -93,7 +93,11 @@ enum { RTM_NEWPREFIX = 52, #define RTM_NEWPREFIX RTM_NEWPREFIX - RTM_GETMULTICAST = 58, + RTM_NEWMULTICAST = 56, +#define RTM_NEWMULTICAST RTM_NEWMULTICAST + RTM_DELMULTICAST, +#define RTM_DELMULTICAST RTM_DELMULTICAST + RTM_GETMULTICAST, #define RTM_GETMULTICAST RTM_GETMULTICAST RTM_GETANYCAST = 62, @@ -774,6 +778,10 @@ enum rtnetlink_groups { #define RTNLGRP_TUNNEL RTNLGRP_TUNNEL RTNLGRP_STATS, #define RTNLGRP_STATS RTNLGRP_STATS + RTNLGRP_IPV4_MCADDR, +#define RTNLGRP_IPV4_MCADDR RTNLGRP_IPV4_MCADDR + RTNLGRP_IPV6_MCADDR, +#define RTNLGRP_IPV6_MCADDR RTNLGRP_IPV6_MCADDR __RTNLGRP_MAX }; #define RTNLGRP_MAX (__RTNLGRP_MAX - 1) diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 6a238398acc9d5..8a370ef37d3f6d 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -88,6 +88,8 @@ #include #include +#include +#include #include #include #include @@ -1430,6 +1432,63 @@ static void ip_mc_hash_remove(struct in_device *in_dev, *mc_hash = im->next_hash; } +static int inet_fill_ifmcaddr(struct sk_buff *skb, struct net_device *dev, + const struct ip_mc_list *im, int event) +{ + struct ifa_cacheinfo ci; + struct ifaddrmsg *ifm; + struct nlmsghdr *nlh; + + nlh = nlmsg_put(skb, 0, 0, event, sizeof(struct ifaddrmsg), 0); + if (!nlh) + return -EMSGSIZE; + + ifm = nlmsg_data(nlh); + ifm->ifa_family = AF_INET; + ifm->ifa_prefixlen = 32; + ifm->ifa_flags = IFA_F_PERMANENT; + ifm->ifa_scope = RT_SCOPE_UNIVERSE; + ifm->ifa_index = dev->ifindex; + + ci.cstamp = (READ_ONCE(im->mca_cstamp) - INITIAL_JIFFIES) * 100UL / HZ; + ci.tstamp = ci.cstamp; + ci.ifa_prefered = INFINITY_LIFE_TIME; + ci.ifa_valid = INFINITY_LIFE_TIME; + + if (nla_put_in_addr(skb, IFA_MULTICAST, im->multiaddr) < 0 || + nla_put(skb, IFA_CACHEINFO, sizeof(ci), &ci) < 0) { + nlmsg_cancel(skb, nlh); + return -EMSGSIZE; + } + + nlmsg_end(skb, nlh); + return 0; +} + +static void inet_ifmcaddr_notify(struct net_device *dev, + const struct ip_mc_list *im, int event) +{ + struct net *net = dev_net(dev); + struct sk_buff *skb; + int err = -ENOMEM; + + skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + + nla_total_size(sizeof(__be32)), GFP_ATOMIC); + if (!skb) + goto error; + + err = inet_fill_ifmcaddr(skb, dev, im, event); + if (err < 0) { + WARN_ON_ONCE(err == -EMSGSIZE); + nlmsg_free(skb); + goto error; + } + + rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MCADDR, NULL, GFP_ATOMIC); + return; +error: + rtnl_set_sk_err(net, RTNLGRP_IPV4_MCADDR, err); +} /* * A socket has joined a multicast group on device dev. @@ -1473,6 +1532,8 @@ static void ____ip_mc_inc_group(struct in_device *in_dev, __be32 addr, im->interface = in_dev; in_dev_hold(in_dev); im->multiaddr = addr; + im->mca_cstamp = jiffies; + im->mca_tstamp = im->mca_cstamp; /* initial mode is (EX, empty) */ im->sfmode = mode; im->sfcount[mode] = 1; @@ -1492,6 +1553,7 @@ static void ____ip_mc_inc_group(struct in_device *in_dev, __be32 addr, igmpv3_del_delrec(in_dev, im); #endif igmp_group_added(im); + inet_ifmcaddr_notify(in_dev->dev, im, RTM_NEWMULTICAST); if (!in_dev->dead) ip_rt_multicast_event(in_dev); out: @@ -1705,6 +1767,8 @@ void __ip_mc_dec_group(struct in_device *in_dev, __be32 addr, gfp_t gfp) *ip = i->next_rcu; in_dev->mc_count--; __igmp_group_dropped(i, gfp); + inet_ifmcaddr_notify(in_dev->dev, i, + RTM_DELMULTICAST); ip_mc_clear_src(i); if (!in_dev->dead) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 0e765466d7f79e..2e2684886953d5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5127,22 +5127,6 @@ static inline int inet6_ifaddr_msgsize(void) + nla_total_size(4) /* IFA_RT_PRIORITY */; } -enum addr_type_t { - UNICAST_ADDR, - MULTICAST_ADDR, - ANYCAST_ADDR, -}; - -struct inet6_fill_args { - u32 portid; - u32 seq; - int event; - unsigned int flags; - int netnsid; - int ifindex; - enum addr_type_t type; -}; - static int inet6_fill_ifaddr(struct sk_buff *skb, const struct inet6_ifaddr *ifa, struct inet6_fill_args *args) @@ -5221,15 +5205,16 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, return -EMSGSIZE; } -static int inet6_fill_ifmcaddr(struct sk_buff *skb, - const struct ifmcaddr6 *ifmca, - struct inet6_fill_args *args) +int inet6_fill_ifmcaddr(struct sk_buff *skb, + const struct ifmcaddr6 *ifmca, + struct inet6_fill_args *args) { int ifindex = ifmca->idev->dev->ifindex; u8 scope = RT_SCOPE_UNIVERSE; struct nlmsghdr *nlh; - if (ipv6_addr_scope(&ifmca->mca_addr) & IFA_SITE) + if (!args->force_rt_scope_universe && + ipv6_addr_scope(&ifmca->mca_addr) & IFA_SITE) scope = RT_SCOPE_SITE; nlh = nlmsg_put(skb, args->portid, args->seq, args->event, @@ -5254,6 +5239,7 @@ static int inet6_fill_ifmcaddr(struct sk_buff *skb, nlmsg_end(skb, nlh); return 0; } +EXPORT_SYMBOL(inet6_fill_ifmcaddr); static int inet6_fill_ifacaddr(struct sk_buff *skb, const struct ifacaddr6 *ifaca, @@ -5418,6 +5404,7 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb, .flags = NLM_F_MULTI, .netnsid = -1, .type = type, + .force_rt_scope_universe = false, }; struct { unsigned long ifindex; @@ -5546,6 +5533,7 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr *nlh, .event = RTM_NEWADDR, .flags = 0, .netnsid = -1, + .force_rt_scope_universe = false, }; struct ifaddrmsg *ifm; struct nlattr *tb[IFA_MAX+1]; @@ -5617,6 +5605,7 @@ static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa) .event = event, .flags = 0, .netnsid = -1, + .force_rt_scope_universe = false, }; int err = -ENOBUFS; diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 5ca8692d565d50..587831c148deec 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -33,8 +33,10 @@ #include #include #include +#include #include #include +#include #include #include #include @@ -47,6 +49,7 @@ #include #include +#include #include #include @@ -901,6 +904,39 @@ static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev, return mc; } +static void inet6_ifmcaddr_notify(struct net_device *dev, + const struct ifmcaddr6 *ifmca, int event) +{ + struct inet6_fill_args fillargs = { + .portid = 0, + .seq = 0, + .event = event, + .flags = 0, + .netnsid = -1, + .force_rt_scope_universe = true, + }; + struct net *net = dev_net(dev); + struct sk_buff *skb; + int err = -ENOMEM; + + skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) + + nla_total_size(16), GFP_ATOMIC); + if (!skb) + goto error; + + err = inet6_fill_ifmcaddr(skb, ifmca, &fillargs); + if (err < 0) { + WARN_ON_ONCE(err == -EMSGSIZE); + nlmsg_free(skb); + goto error; + } + + rtnl_notify(skb, net, 0, RTNLGRP_IPV6_MCADDR, NULL, GFP_ATOMIC); + return; +error: + rtnl_set_sk_err(net, RTNLGRP_IPV6_MCADDR, err); +} + /* * device multicast group inc (add if not found) */ @@ -948,6 +984,7 @@ static int __ipv6_dev_mc_inc(struct net_device *dev, mld_del_delrec(idev, mc); igmp6_group_added(mc); + inet6_ifmcaddr_notify(dev, mc, RTM_NEWMULTICAST); mutex_unlock(&idev->mc_lock); ma_put(mc); return 0; @@ -977,6 +1014,8 @@ int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr) *map = ma->next; igmp6_group_dropped(ma); + inet6_ifmcaddr_notify(idev->dev, ma, + RTM_DELMULTICAST); ip6_mc_clear_src(ma); mutex_unlock(&idev->mc_lock);