Hi Roopa inline
thx -pr On Fri, 2018-08-31 at 09:29 -0700, Roopa Prabhu wrote: > On Fri, Aug 31, 2018 at 4:20 AM, Patrick Ruddy > <pru...@vyatta.att-mail.com> wrote: > > Some userspace applications need to know about IGMP joins from the kernel > > for 2 reasons > > 1. To allow the programming of multicast MAC filters in hardware > > 2. To form a multicast FORUS list for non link-local multicast > > groups to be sent to the kernel and from there to the interested > > party. > > (1) can be fulfilled but simply sending the hardware multicast MAC > > address to be programmed but (2) requires the L3 address to be sent > > since this cannot be constructed from the MAC address whereas the > > reverse translation is a standard library function. > > > > This commit provides addition and deletion of multicast addresses > > using the RTM_NEWADDR and RTM_DELADDR messages. It also provides > > the RTM_GETADDR extension to allow multicast join state to be read > > from the kernel. > > > > Signed-off-by: Patrick Ruddy <pru...@vyatta.att-mail.com> > > --- > > v2: fix kbuild warnings. > > I am still going through the series, but AFAICT, user-space caches listening > to > RTNLGRP_IPV4_IFADDR will now also get multicast addresses by default ? > Yes that's the crux of this change. It's unfortunate that I could not use IFA_MULTICAST to distinguish the SAFI. I suppose the other option would be to create a set of new NEW/DEL/GETMULTICAST messages but the partial code for RTM_GETMULTICAST in ipv6/mcast.c complicates that slightly. Happy to look at it if you think that would be be better. > > > > > include/linux/igmp.h | 4 ++ > > net/ipv4/devinet.c | 39 +++++++++++++------ > > net/ipv4/igmp.c | 90 ++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 122 insertions(+), 11 deletions(-) > > > > diff --git a/include/linux/igmp.h b/include/linux/igmp.h > > index 119f53941c12..644a548024ed 100644 > > --- a/include/linux/igmp.h > > +++ b/include/linux/igmp.h > > @@ -19,6 +19,8 @@ > > #include <linux/timer.h> > > #include <linux/in.h> > > #include <linux/refcount.h> > > +#include <linux/netlink.h> > > +#include <linux/netdevice.h> > > #include <uapi/linux/igmp.h> > > > > static inline struct igmphdr *igmp_hdr(const struct sk_buff *skb) > > @@ -130,6 +132,8 @@ extern void ip_mc_unmap(struct in_device *); > > extern void ip_mc_remap(struct in_device *); > > extern void ip_mc_dec_group(struct in_device *in_dev, __be32 addr); > > extern void ip_mc_inc_group(struct in_device *in_dev, __be32 addr); > > +extern int ip_mc_dump_ifaddr(struct sk_buff *skb, struct netlink_callback > > *cb, > > + struct net_device *dev); > > int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed); > > > > #endif > > diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c > > index ea4bd8a52422..42f7dcc4fb5e 100644 > > --- a/net/ipv4/devinet.c > > +++ b/net/ipv4/devinet.c > > @@ -57,6 +57,7 @@ > > #endif > > #include <linux/kmod.h> > > #include <linux/netconf.h> > > +#include <linux/igmp.h> > > > > #include <net/arp.h> > > #include <net/ip.h> > > @@ -1651,6 +1652,7 @@ static int inet_dump_ifaddr(struct sk_buff *skb, > > struct netlink_callback *cb) > > int h, s_h; > > int idx, s_idx; > > int ip_idx, s_ip_idx; > > + int multicast, mcast_idx; > > struct net_device *dev; > > struct in_device *in_dev; > > struct in_ifaddr *ifa; > > @@ -1659,6 +1661,8 @@ static int inet_dump_ifaddr(struct sk_buff *skb, > > struct netlink_callback *cb) > > s_h = cb->args[0]; > > s_idx = idx = cb->args[1]; > > s_ip_idx = ip_idx = cb->args[2]; > > + multicast = cb->args[3]; > > + mcast_idx = cb->args[4]; > > > > for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { > > idx = 0; > > @@ -1675,18 +1679,29 @@ static int inet_dump_ifaddr(struct sk_buff *skb, > > struct netlink_callback *cb) > > if (!in_dev) > > goto cont; > > > > - for (ifa = in_dev->ifa_list, ip_idx = 0; ifa; > > - ifa = ifa->ifa_next, ip_idx++) { > > - if (ip_idx < s_ip_idx) > > - continue; > > - if (inet_fill_ifaddr(skb, ifa, > > - NETLINK_CB(cb->skb).portid, > > - cb->nlh->nlmsg_seq, > > - RTM_NEWADDR, NLM_F_MULTI) < 0) > > { > > - rcu_read_unlock(); > > - goto done; > > + if (!multicast) { > > + for (ifa = in_dev->ifa_list, ip_idx = 0; > > ifa; > > + ifa = ifa->ifa_next, ip_idx++) { > > + if (ip_idx < s_ip_idx) > > + continue; > > + if (inet_fill_ifaddr(skb, ifa, > > + > > NETLINK_CB(cb->skb).portid, > > + > > cb->nlh->nlmsg_seq, > > + RTM_NEWADDR, > > + NLM_F_MULTI) < > > 0) { > > + rcu_read_unlock(); > > + goto done; > > + } > > + nl_dump_check_consistent(cb, > > + > > nlmsg_hdr(skb)); > > } > > - nl_dump_check_consistent(cb, > > nlmsg_hdr(skb)); > > + /* set for multicast loop */ > > + multicast++; > > + } > > + /* loop over multicast addresses */ > > + if (ip_mc_dump_ifaddr(skb, cb, dev) < 0) { > > + rcu_read_unlock(); > > + goto done; > > } > > cont: > > idx++; > > @@ -1698,6 +1713,8 @@ static int inet_dump_ifaddr(struct sk_buff *skb, > > struct netlink_callback *cb) > > cb->args[0] = h; > > cb->args[1] = idx; > > cb->args[2] = ip_idx; > > + cb->args[3] = multicast; > > + cb->args[4] = mcast_idx; > > > > return skb->len; > > } > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > > index cf75f8944b05..c9bbd1d27124 100644 > > --- a/net/ipv4/igmp.c > > +++ b/net/ipv4/igmp.c > > @@ -86,6 +86,7 @@ > > #include <linux/inetdevice.h> > > #include <linux/igmp.h> > > #include <linux/if_arp.h> > > +#include <net/netlink.h> > > #include <linux/rtnetlink.h> > > #include <linux/times.h> > > #include <linux/pkt_sched.h> > > @@ -1384,6 +1385,91 @@ static void ip_mc_hash_remove(struct in_device > > *in_dev, > > } > > > > > > +static int fill_addr(struct sk_buff *skb, struct net_device *dev, __be32 > > addr, > > + int type, unsigned int flags) > > +{ > > + struct nlmsghdr *nlh; > > + struct ifaddrmsg *ifm; > > + > > + nlh = nlmsg_put(skb, 0, 0, type, sizeof(*ifm), flags); > > + 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_LINK; > > + ifm->ifa_index = dev->ifindex; > > + > > + if (nla_put_in_addr(skb, IFA_ADDRESS, addr)) > > + goto nla_put_failure; > > + nlmsg_end(skb, nlh); > > + return 0; > > + > > +nla_put_failure: > > + nlmsg_cancel(skb, nlh); > > + return -EMSGSIZE; > > +} > > + > > +static inline size_t addr_nlmsg_size(void) > > +{ > > + return NLMSG_ALIGN(sizeof(struct ifaddrmsg)) > > + + nla_total_size(sizeof(__be32)); > > +} > > + > > +static void ip_mc_addr_notify(struct net_device *dev, __be32 addr, int > > type) > > +{ > > + struct net *net = dev_net(dev); > > + struct sk_buff *skb; > > + int err = -ENOBUFS; > > + > > + skb = nlmsg_new(addr_nlmsg_size(), GFP_ATOMIC); > > + if (!skb) > > + goto errout; > > + > > + err = fill_addr(skb, dev, addr, type, 0); > > + if (err < 0) { > > + WARN_ON(err == -EMSGSIZE); > > + kfree_skb(skb); > > + goto errout; > > + } > > + rtnl_notify(skb, net, 0, RTNLGRP_IPV4_IFADDR, NULL, GFP_ATOMIC); > > + return; > > +errout: > > + if (err < 0) > > + rtnl_set_sk_err(net, RTNLGRP_LINK, err); > > > s/RTNLGRP_LINK/RTNLGRP_IPV4_IFADDR/ > > > > > > +} > > + > > +int ip_mc_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb, > > + struct net_device *dev) > > +{ > > + int s_idx; > > + int idx = 0; > > + struct ip_mc_list *im; > > + struct in_device *in_dev; > > + > > + ASSERT_RTNL(); > > + > > + s_idx = cb->args[4]; > > + in_dev = __in_dev_get_rtnl(dev); > > + > > + for_each_pmc_rtnl(in_dev, im) { > > + if (idx < s_idx) > > + continue; > > + if (fill_addr(skb, dev, im->multiaddr, RTM_NEWADDR, > > + NLM_F_MULTI) < 0) > > + goto done; > > + nl_dump_check_consistent(cb, nlmsg_hdr(skb)); > > + idx++; > > + } > > + > > + done: > > + cb->args[4] = idx; > > + > > + return skb->len; > > +} > > + > > /* > > * A socket has joined a multicast group on device dev. > > */ > > @@ -1433,6 +1519,8 @@ static void __ip_mc_inc_group(struct in_device > > *in_dev, __be32 addr, > > igmpv3_del_delrec(in_dev, im); > > #endif > > igmp_group_added(im); > > + > > + ip_mc_addr_notify(in_dev->dev, addr, RTM_NEWADDR); > > if (!in_dev->dead) > > ip_rt_multicast_event(in_dev); > > out: > > @@ -1664,6 +1752,8 @@ void ip_mc_dec_group(struct in_device *in_dev, __be32 > > addr) > > in_dev->mc_count--; > > igmp_group_dropped(i); > > ip_mc_clear_src(i); > > + ip_mc_addr_notify(in_dev->dev, addr, > > + RTM_DELADDR); > > > > if (!in_dev->dead) > > ip_rt_multicast_event(in_dev); > > -- > > 2.17.1 > >