[PATCH 15/24] net, diet: Make igmp and mcast ioctls depend on IP_MULTICAST

Andi Kleen
2014-05-05T22:31:09Z

From: Andi Kleen <ak@linux.intel.com>

There was already a CONFIG_IP_MULTICAST, but it didn't control
the multicasting code (like igmp) in the IP stack, only some
driver code. Change this.

This disables some multi cast filters in TCP/UDP too, but
that should be ok because we never joing multicast groups
without this options, so the packets should never arrive up-stack.

Worth ~20k when disabled

text data bss dec hex filename
420363 17509 11624 449496 6dbd8 net/built-in.o-with-mcast
399649 17381 11624 428654 68a6e net/built-in.o-wo-mcast

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
include/linux/igmp.h | 31 +++++++++++++++++++++++--------
net/ipv4/Kconfig | 8 +++-----
net/ipv4/Makefile | 3 ++-
net/ipv4/devinet.c | 2 ++
net/ipv4/ip_sockglue.c | 4 ++++
net/ipv4/sysctl_net_ipv4.c | 2 ++
6 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index f47550d..1a1a044 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -108,11 +108,7 @@ struct ip_mc_list {
#define IGMPV3_QQIC(value) IGMPV3_EXP(0x80, 4, 3, value)
#define IGMPV3_MRC(value) IGMPV3_EXP(0x80, 4, 3, value)

-extern int ip_check_mc_rcu(struct in_device *dev, __be32 mc_addr, __be32 src_addr, u16 proto);
extern int igmp_rcv(struct sk_buff *);
-extern int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr);
-extern int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr);
-extern void ip_mc_drop_socket(struct sock *sk);
extern int ip_mc_source(int add, int omode, struct sock *sk,
struct ip_mreq_source *mreqs, int ifindex);
extern int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf,int ifindex);
@@ -120,14 +116,33 @@ extern int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
struct ip_msfilter __user *optval, int __user *optlen);
extern int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
struct group_filter __user *optval, int __user *optlen);
-extern int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt, int dif);
-extern void ip_mc_init_dev(struct in_device *);
-extern void ip_mc_destroy_dev(struct in_device *);
-extern void ip_mc_up(struct in_device *);
extern void ip_mc_down(struct in_device *);
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);

+#ifdef CONFIG_IP_MULTICAST
+extern int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt, int dif);
+extern int ip_check_mc_rcu(struct in_device *dev, __be32 mc_addr, __be32 src_addr, u16 proto);
+extern void ip_mc_up(struct in_device *);
+extern void ip_mc_destroy_dev(struct in_device *);
+extern void ip_mc_init_dev(struct in_device *);
+extern void ip_mc_drop_socket(struct sock *sk);
+extern int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr);
+extern int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr);
+#else
+static inline int ip_mc_sf_allow(struct sock *sk, __be32 local, __be32 rmt, int dif)
+{ return 0; }
+static inline int ip_check_mc_rcu(struct in_device *dev, __be32 mc_addr, __be32 src_addr, u16 proto)
+{ return 0; }
+static inline void ip_mc_up(struct in_device *d) {}
+static inline void ip_mc_destroy_dev(struct in_device *d) {}
+static inline void ip_mc_init_dev(struct in_device *d) {}
+static inline void ip_mc_drop_socket(struct sock *sk) {}
+static inline int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr)
+{ return -EINVAL; }
+static inline int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr)
+{ return -EINVAL; }
+#endif
#endif
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 00a7f76..c1f9899 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -5,11 +5,9 @@ config IP_MULTICAST
bool "IP: multicasting"
help
This is code for addressing several networked computers at once,
- enlarging your kernel by about 2 KB. You need multicasting if you
- intend to participate in the MBONE, a high bandwidth network on top
- of the Internet which carries audio and video broadcasts. More
- information about the MBONE is on the WWW at
- <http://www.savetz.com/mbone/>. For most people, it's safe to say N.
+ enlarging your kernel by about 20 KB. This is needed for many
+ modern networking services on the local network, so you should
+ probably say Y.

config IP_ADVANCED_ROUTER
bool "IP: advanced router"
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 784a782..eb129a4 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -9,7 +9,7 @@ obj-y := route.o inetpeer.o protocol.o \
tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
tcp_minisocks.o tcp_cong.o tcp_fastopen.o \
datagram.o raw.o udp.o udplite.o \
- arp.o icmp.o devinet.o af_inet.o igmp.o \
+ arp.o icmp.o devinet.o af_inet.o \
fib_frontend.o fib_semantics.o fib_trie.o \
inet_fragment.o ip_tunnel_core.o gre_offload.o

@@ -37,6 +37,7 @@ obj-$(CONFIG_INET_TUNNEL) += tunnel4.o
obj-$(CONFIG_INET_XFRM_MODE_TRANSPORT) += xfrm4_mode_transport.o
obj-$(CONFIG_INET_XFRM_MODE_TUNNEL) += xfrm4_mode_tunnel.o
obj-$(CONFIG_IP_PNP) += ipconfig.o
+obj-$(CONFIG_IP_MULTICAST) += igmp.o
obj-$(CONFIG_NETFILTER) += netfilter.o netfilter/
obj-$(CONFIG_INET_DIAG) += inet_diag.o
obj-$(CONFIG_INET_TCP_DIAG) += tcp_diag.o
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index bdbf68b..c19266d 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1402,6 +1402,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
/* Send gratuitous ARP to notify of link change */
inetdev_send_gratuitous_arp(dev, in_dev);
break;
+#ifdef CONFIG_IP_MULTICAST
case NETDEV_DOWN:
ip_mc_down(in_dev);
break;
@@ -1411,6 +1412,7 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
case NETDEV_POST_TYPE_CHANGE:
ip_mc_remap(in_dev);
break;
+#endif
case NETDEV_CHANGEMTU:
if (inetdev_valid_mtu(dev->mtu))
break;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 64741b9..ed5c7bd 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -652,6 +652,7 @@ static int do_ip_setsockopt(struct sock *sk, int level,
if (!val)
skb_queue_purge(&sk->sk_error_queue);
break;
+#ifdef CONFIG_IP_MULTICAST
case IP_MULTICAST_TTL:
if (sk->sk_type == SOCK_STREAM)
goto e_inval;
@@ -1010,6 +1011,7 @@ mc_msf_out:
goto e_inval;
inet->mc_all = val;
break;
+#endif
case IP_ROUTER_ALERT:
err = ip_ra_control(sk, val ? 1 : 0, NULL);
break;
@@ -1248,6 +1250,7 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_RECVERR:
val = inet->recverr;
break;
+#ifdef CONFIG_IP_MULTICAST
case IP_MULTICAST_TTL:
val = inet->mc_ttl;
break;
@@ -1310,6 +1313,7 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_MULTICAST_ALL:
val = inet->mc_all;
break;
+#endif
case IP_PKTOPTIONS:
{
struct msghdr msg;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 2110d2e..fe5823a 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -443,6 +443,7 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_do_large_bitmap,
},
+#ifdef CONFIG_IP_MULTICAST
{
.procname = "igmp_max_memberships",
.data = &sysctl_igmp_max_memberships,
@@ -457,6 +458,7 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
+#endif
{
.procname = "inet_peer_threshold",
.data = &inet_peer_threshold,
--
1.9.0