| Message ID | 4A1EC33E.1080201@us.ibm.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thursday 28 May 2009 20:00:46 ext Nivedita Singhvi wrote: > After some discussion offline with Christoph Lameter and David Stevens > regarding multicast behaviour in Linux, I'm submitting a slightly > modified patch from the one Christoph submitted earlier. > > This patch provides a new socket option IP_MULTICAST_ALL. > > In this case, default behaviour is _unchanged_ from the current > Linux standard. The socket option is set by default to provide > original behaviour. Sockets wishing to receive data only from > multicast groups they join explicitly will need to clear this > socket option. You can already achieve this by checking the destination address in the SOL_PKTINFO ancilliary data. Sure, it will cause extra context switches to process unwanted packets but it will work with any kernel version.
On Thu, May 28, 2009 at 10:00:46AM -0700, Nivedita Singhvi wrote: > After some discussion offline with Christoph Lameter and David Stevens > regarding multicast behaviour in Linux, I'm submitting a slightly > modified patch from the one Christoph submitted earlier. > > This patch provides a new socket option IP_MULTICAST_ALL. > > In this case, default behaviour is _unchanged_ from the current > Linux standard. The socket option is set by default to provide original > behaviour. Sockets wishing to receive data only from multicast groups > they join explicitly will need to clear this socket option. > > > Signed-off-by: Nivedita Singhvi <niv@us.ibm.com> > Signed-off-by: Christoph Lameter<cl@linux.com> > Acked-by: David Stevens <dlstevens@us.ibm.com> > > > diff -urN linux-2.6.29.2/include/linux/in.h linux-2.6.29.2.new/include/linux/in.h > --- linux-2.6.29.2/include/linux/in.h 2009-04-27 13:37:11.000000000 -0400 > +++ linux-2.6.29.2.new/include/linux/in.h 2009-05-18 16:22:06.000000000 -0400 > @@ -107,6 +107,7 @@ > #define MCAST_JOIN_SOURCE_GROUP 46 > #define MCAST_LEAVE_SOURCE_GROUP 47 > #define MCAST_MSFILTER 48 > +#define IP_MULTICAST_ALL 49 > > #define MCAST_EXCLUDE 0 > #define MCAST_INCLUDE 1 > diff -urN linux-2.6.29.2/include/net/inet_sock.h linux-2.6.29.2.new/include/net/inet_sock.h > --- linux-2.6.29.2/include/net/inet_sock.h 2009-04-27 13:37:11.000000000 -0400 > +++ linux-2.6.29.2.new/include/net/inet_sock.h 2009-05-18 16:22:06.000000000 -0400 > @@ -130,7 +130,8 @@ > freebind:1, > hdrincl:1, > mc_loop:1, > - transparent:1; > + transparent:1, > + mc_all:1; > int mc_index; > __be32 mc_addr; > struct ip_mc_socklist *mc_list; > diff -urN linux-2.6.29.2/net/ipv4/af_inet.c linux-2.6.29.2.new/net/ipv4/af_inet.c > --- linux-2.6.29.2/net/ipv4/af_inet.c 2009-04-27 13:37:11.000000000 -0400 > +++ linux-2.6.29.2.new/net/ipv4/af_inet.c 2009-05-18 16:22:06.000000000 -0400 > @@ -376,6 +376,7 @@ > inet->uc_ttl = -1; > inet->mc_loop = 1; > inet->mc_ttl = 1; > + inet->mc_all = 1; > inet->mc_index = 0; > inet->mc_list = NULL; > > diff -urN linux-2.6.29.2/net/ipv4/igmp.c linux-2.6.29.2.new/net/ipv4/igmp.c > --- linux-2.6.29.2/net/ipv4/igmp.c 2009-04-27 13:37:11.000000000 -0400 > +++ linux-2.6.29.2.new/net/ipv4/igmp.c 2009-05-18 16:22:33.000000000 -0400 > @@ -2196,7 +2196,7 @@ > break; > } > if (!pmc) > - return 1; > + return inet->mc_all; This change also filters out broadcasts sent to sockets listening on a given port. Is that what you want? Neil > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 29 May 2009, Neil Horman wrote: > > diff -urN linux-2.6.29.2/net/ipv4/igmp.c linux-2.6.29.2.new/net/ipv4/igmp.c > > --- linux-2.6.29.2/net/ipv4/igmp.c 2009-04-27 13:37:11.000000000 -0400 > > +++ linux-2.6.29.2.new/net/ipv4/igmp.c 2009-05-18 16:22:33.000000000 -0400 > > @@ -2196,7 +2196,7 @@ > > break; > > } > > if (!pmc) > > - return 1; > > + return inet->mc_all; > > This change also filters out broadcasts sent to sockets listening on a given > port. Is that what you want? Look at the beginning of the function: if (!ipv4_is_multicast(loc_addr)) return 1; will return 1 for broadcast. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Rémi Denis-Courmont wrote: >> In this case, default behaviour is _unchanged_ from the current >> Linux standard. The socket option is set by default to provide >> original behaviour. Sockets wishing to receive data only from >> multicast groups they join explicitly will need to clear this >> socket option. > > You can already achieve this by checking the destination address in the > SOL_PKTINFO ancilliary data. Sure, it will cause extra context switches to > process unwanted packets but it will work with any kernel version. > True, and depending on your environment and workload, this is a non-event or a big deal. For low latency, real time and other performance-sensitive applications, this can be an issue. Think lots (hundreds of threads, perhaps) listening on different channels(groups). They will likely all get woken, scheduled, possibly preempt running lower-priority tasks to process this delivery that they don't need. Seen across the system, the delivery by the kernel of packets to user space processes which don't want them can be very significant overhead (context switches, scheduling out/in,...). thanks, Nivedita -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Neil Horman wrote: >> if (!pmc) >> - return 1; >> + return inet->mc_all; > > This change also filters out broadcasts sent to sockets listening on a given > port. Is that what you want? Yes, as Christoph pointed out, this does not impact broadcast delivery, which will remain consistent with original behaviour. thanks, Nivedita -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Nivedita Singhvi <niv@us.ibm.com> Date: Thu, 28 May 2009 10:00:46 -0700 > After some discussion offline with Christoph Lameter and David Stevens > regarding multicast behaviour in Linux, I'm submitting a slightly > modified patch from the one Christoph submitted earlier. > > This patch provides a new socket option IP_MULTICAST_ALL. > > In this case, default behaviour is _unchanged_ from the current > Linux standard. The socket option is set by default to provide > original behaviour. Sockets wishing to receive data only from > multicast groups they join explicitly will need to clear this socket > option. > > > Signed-off-by: Nivedita Singhvi <niv@us.ibm.com> > Signed-off-by: Christoph Lameter<cl@linux.com> > Acked-by: David Stevens <dlstevens@us.ibm.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff -urN linux-2.6.29.2/include/linux/in.h linux-2.6.29.2.new/include/linux/in.h --- linux-2.6.29.2/include/linux/in.h 2009-04-27 13:37:11.000000000 -0400 +++ linux-2.6.29.2.new/include/linux/in.h 2009-05-18 16:22:06.000000000 -0400 @@ -107,6 +107,7 @@ #define MCAST_JOIN_SOURCE_GROUP 46 #define MCAST_LEAVE_SOURCE_GROUP 47 #define MCAST_MSFILTER 48 +#define IP_MULTICAST_ALL 49 #define MCAST_EXCLUDE 0 #define MCAST_INCLUDE 1 diff -urN linux-2.6.29.2/include/net/inet_sock.h linux-2.6.29.2.new/include/net/inet_sock.h --- linux-2.6.29.2/include/net/inet_sock.h 2009-04-27 13:37:11.000000000 -0400 +++ linux-2.6.29.2.new/include/net/inet_sock.h 2009-05-18 16:22:06.000000000 -0400 @@ -130,7 +130,8 @@ freebind:1, hdrincl:1, mc_loop:1, - transparent:1; + transparent:1, + mc_all:1; int mc_index; __be32 mc_addr; struct ip_mc_socklist *mc_list; diff -urN linux-2.6.29.2/net/ipv4/af_inet.c linux-2.6.29.2.new/net/ipv4/af_inet.c --- linux-2.6.29.2/net/ipv4/af_inet.c 2009-04-27 13:37:11.000000000 -0400 +++ linux-2.6.29.2.new/net/ipv4/af_inet.c 2009-05-18 16:22:06.000000000 -0400 @@ -376,6 +376,7 @@ inet->uc_ttl = -1; inet->mc_loop = 1; inet->mc_ttl = 1; + inet->mc_all = 1; inet->mc_index = 0; inet->mc_list = NULL; diff -urN linux-2.6.29.2/net/ipv4/igmp.c linux-2.6.29.2.new/net/ipv4/igmp.c --- linux-2.6.29.2/net/ipv4/igmp.c 2009-04-27 13:37:11.000000000 -0400 +++ linux-2.6.29.2.new/net/ipv4/igmp.c 2009-05-18 16:22:33.000000000 -0400 @@ -2196,7 +2196,7 @@ break; } if (!pmc) - return 1; + return inet->mc_all; psl = pmc->sflist; if (!psl) return pmc->sfmode == MCAST_EXCLUDE; diff -urN linux-2.6.29.2/net/ipv4/ip_sockglue.c linux-2.6.29.2.new/net/ipv4/ip_sockglue.c --- linux-2.6.29.2/net/ipv4/ip_sockglue.c 2009-04-27 13:37:11.000000000 -0400 +++ linux-2.6.29.2.new/net/ipv4/ip_sockglue.c 2009-05-18 16:22:06.000000000 -0400 @@ -449,6 +449,7 @@ (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) | (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT))) || optname == IP_MULTICAST_TTL || + optname == IP_MULTICAST_ALL || optname == IP_MULTICAST_LOOP || optname == IP_RECVORIGDSTADDR) { if (optlen >= sizeof(int)) { @@ -895,6 +896,13 @@ kfree(gsf); break; } + case IP_MULTICAST_ALL: + if (optlen<1) + goto e_inval; + if (val != 0 && val != 1) + goto e_inval; + inet->mc_all = val; + break; case IP_ROUTER_ALERT: err = ip_ra_control(sk, val ? 1 : 0, NULL); break; @@ -1147,6 +1155,9 @@ release_sock(sk); return err; } + case IP_MULTICAST_ALL: + val = inet->mc_all; + break; case IP_PKTOPTIONS: { struct msghdr msg;