linux/include/net/ipv6.h

919 lines
26 KiB

net: increase fragment memory usage limits Increase the amount of memory usage limits for incomplete IP fragments. Arguing for new thresh high/low values: High threshold = 4 MBytes Low threshold = 3 MBytes The fragmentation memory accounting code, tries to account for the real memory usage, by measuring both the size of frag queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) and the SKB's truesize. We want to be able to handle/hold-on-to enough fragments, to ensure good performance, without causing incomplete fragments to hurt scalability, by causing the number of inet_frag_queue to grow too much (resulting longer searches for frag queues). For IPv4, how much memory does the largest frag consume. Maximum size fragment is 64K, which is approx 44 fragments with MTU(1500) sized packets. Sizeof(struct ipq) is 200. A 1500 byte packet results in a truesize of 2944 (not 2048 as I first assumed) (44*2944)+200 = 129736 bytes The current default high thresh of 262144 bytes, is obviously problematic, as only two 64K fragments can fit in the queue at the same time. How many 64K fragment can we fit into 4 MBytes: 4*2^20/((44*2944)+200) = 32.34 fragment in queues An attacker could send a separate/distinct fake fragment packets per queue, causing us to allocate one inet_frag_queue per packet, and thus attacking the hash table and its lists. How many frag queue do we need to store, and given a current hash size of 64, what is the average list length. Using one MTU sized fragment per inet_frag_queue, each consuming (2944+200) 3144 bytes. 4*2^20/(2944+200) = 1334 frag queues -> 21 avg list length An attack could send small fragments, the smallest packet I could send resulted in a truesize of 896 bytes (I'm a little surprised by this). 4*2^20/(896+200) = 3827 frag queues -> 59 avg list length When increasing these number, we also need to followup with improvements, that is going to help scalability. Simply increasing the hash size, is not enough as the current implementation does not have a per hash bucket locking. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-15 07:16:35 +00:00
net: provide stubs for ip6_set_txhash and ip6_make_flowlabel Commit cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit") introduced ip6_make_flowlabel, while commit b73c3d0e4f0e ("net: Save TX flow hash in sock and set in skbuf on xmit") introduced ip6_set_txhash. ip6_set_tx_hash() uses sk_v6_daddr which references __sk_common.skc_v6_daddr from struct sock_common, which is gated with IS_ENABLED(CONFIG_IPV6). ip6_make_flowlabel() uses the ipv6 member from struct net which is also gated with IS_ENABLED(CONFIG_IPV6). When CONFIG_IPV6 is disabled, we will hit a build failure that looks like this when the compiler attempts inlining these functions: CC [M] drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.o In file included from include/net/inet_sock.h:27:0, from include/net/ip.h:30, from drivers/net/ethernet/broadcom/cnic.c:37: include/net/ipv6.h: In function 'ip6_set_txhash': include/net/sock.h:327:33: error: 'struct sock_common' has no member named 'skc_v6_daddr' #define sk_v6_daddr __sk_common.skc_v6_daddr ^ include/net/ipv6.h:696:49: note: in expansion of macro 'sk_v6_daddr' keys.dst = (__force __be32)ipv6_addr_hash(&sk->sk_v6_daddr); ^ In file included from include/net/inetpeer.h:15:0, from include/net/route.h:28, from include/net/ip.h:31, from drivers/net/ethernet/broadcom/cnic.c:37: include/net/ipv6.h: In function 'ip6_make_flowlabel': include/net/ipv6.h:706:37: error: 'struct net' has no member named 'ipv6' if (!flowlabel && (autolabel || net->ipv6.sysctl.auto_flowlabels)) { ^ Fixes: cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit") Fixes: b73c3d0e4f0e ("net: Save TX flow hash in sock and set in skbuf on xmit") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-08 11:15:03 -07:00
ipv6: Implement automatic flow label generation on transmit Automatically generate flow labels for IPv6 packets on transmit. The flow label is computed based on skb_get_hash. The flow label will only automatically be set when it is zero otherwise (i.e. flow label manager hasn't set one). This supports the transmit side functionality of RFC 6438. Added an IPv6 sysctl auto_flowlabels to enable/disable this behavior system wide, and added IPV6_AUTOFLOWLABEL socket option to enable this functionality per socket. By default, auto flowlabels are disabled to avoid possible conflicts with flow label manager, however if this feature proves useful we may want to enable it by default. It should also be noted that FreeBSD has already implemented automatic flow labels (including the sysctl and socket option). In FreeBSD, automatic flow labels default to enabled. Performance impact: Running super_netperf with 200 flows for TCP_RR and UDP_RR for IPv6. Note that in UDP case, __skb_get_hash will be called for every packet with explains slight regression. In the TCP case the hash is saved in the socket so there is no regression. Automatic flow labels disabled: TCP_RR: 86.53% CPU utilization 127/195/322 90/95/99% latencies 1.40498e+06 tps UDP_RR: 90.70% CPU utilization 118/168/243 90/95/99% latencies 1.50309e+06 tps Automatic flow labels enabled: TCP_RR: 85.90% CPU utilization 128/199/337 90/95/99% latencies 1.40051e+06 UDP_RR 92.61% CPU utilization 115/164/236 90/95/99% latencies 1.4687e+06 Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-01 21:33:10 -07:00
net: provide stubs for ip6_set_txhash and ip6_make_flowlabel Commit cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit") introduced ip6_make_flowlabel, while commit b73c3d0e4f0e ("net: Save TX flow hash in sock and set in skbuf on xmit") introduced ip6_set_txhash. ip6_set_tx_hash() uses sk_v6_daddr which references __sk_common.skc_v6_daddr from struct sock_common, which is gated with IS_ENABLED(CONFIG_IPV6). ip6_make_flowlabel() uses the ipv6 member from struct net which is also gated with IS_ENABLED(CONFIG_IPV6). When CONFIG_IPV6 is disabled, we will hit a build failure that looks like this when the compiler attempts inlining these functions: CC [M] drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.o In file included from include/net/inet_sock.h:27:0, from include/net/ip.h:30, from drivers/net/ethernet/broadcom/cnic.c:37: include/net/ipv6.h: In function 'ip6_set_txhash': include/net/sock.h:327:33: error: 'struct sock_common' has no member named 'skc_v6_daddr' #define sk_v6_daddr __sk_common.skc_v6_daddr ^ include/net/ipv6.h:696:49: note: in expansion of macro 'sk_v6_daddr' keys.dst = (__force __be32)ipv6_addr_hash(&sk->sk_v6_daddr); ^ In file included from include/net/inetpeer.h:15:0, from include/net/route.h:28, from include/net/ip.h:31, from drivers/net/ethernet/broadcom/cnic.c:37: include/net/ipv6.h: In function 'ip6_make_flowlabel': include/net/ipv6.h:706:37: error: 'struct net' has no member named 'ipv6' if (!flowlabel && (autolabel || net->ipv6.sysctl.auto_flowlabels)) { ^ Fixes: cb1ce2ef387b ("ipv6: Implement automatic flow label generation on transmit") Fixes: b73c3d0e4f0e ("net: Save TX flow hash in sock and set in skbuf on xmit") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-08 11:15:03 -07:00
ipv6: Implement automatic flow label generation on transmit Automatically generate flow labels for IPv6 packets on transmit. The flow label is computed based on skb_get_hash. The flow label will only automatically be set when it is zero otherwise (i.e. flow label manager hasn't set one). This supports the transmit side functionality of RFC 6438. Added an IPv6 sysctl auto_flowlabels to enable/disable this behavior system wide, and added IPV6_AUTOFLOWLABEL socket option to enable this functionality per socket. By default, auto flowlabels are disabled to avoid possible conflicts with flow label manager, however if this feature proves useful we may want to enable it by default. It should also be noted that FreeBSD has already implemented automatic flow labels (including the sysctl and socket option). In FreeBSD, automatic flow labels default to enabled. Performance impact: Running super_netperf with 200 flows for TCP_RR and UDP_RR for IPv6. Note that in UDP case, __skb_get_hash will be called for every packet with explains slight regression. In the TCP case the hash is saved in the socket so there is no regression. Automatic flow labels disabled: TCP_RR: 86.53% CPU utilization 127/195/322 90/95/99% latencies 1.40498e+06 tps UDP_RR: 90.70% CPU utilization 118/168/243 90/95/99% latencies 1.50309e+06 tps Automatic flow labels enabled: TCP_RR: 85.90% CPU utilization 128/199/337 90/95/99% latencies 1.40051e+06 UDP_RR 92.61% CPU utilization 115/164/236 90/95/99% latencies 1.4687e+06 Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-01 21:33:10 -07:00