kernel/linux.git/include/net/inet_sock.h, branch v4.12.9

net/tcp-fastopen: Add new API support

2017-01-25T19:04:38+00:00

This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang Acked-by: Eric Dumazet Acked-by: Yuchung Cheng Signed-off-by: David S. Miller

ipv4: add IP_RECVFRAGSIZE cmsg

2016-11-03T19:41:11+00:00

The IP stack records the largest fragment of a reassembled packet in IPCB(skb)->frag_max_size. When reading a datagram or raw packet that arrived fragmented, expose the value to allow applications to estimate receive path MTU. Tested: Sent data over a veth pair of which the source has a small mtu. Sent data using netcat, received using a dedicated process. Verified that the cmsg IP_RECVFRAGSIZE is returned only when data arrives fragmented, and in that cases matches the veth mtu. ip link add veth0 type veth peer name veth1 ip netns add from ip netns add to ip link set dev veth1 netns to ip netns exec to ip addr add dev veth1 192.168.10.1/24 ip netns exec to ip link set dev veth1 up ip link set dev veth0 netns from ip netns exec from ip addr add dev veth0 192.168.10.2/24 ip netns exec from ip link set dev veth0 up ip netns exec from ip link set dev veth0 mtu 1300 ip netns exec from ethtool -K veth0 ufo off dd if=/dev/zero bs=1 count=1400 2>/dev/null > payload ip netns exec to ./recv_cmsg_recvfragsize -4 -u -p 6000 & ip netns exec from nc -q 1 -u 192.168.10.1 6000 < payload using github.com/wdebruij/kerneltools/blob/master/tests/recvfragsize.c Signed-off-by: Willem de Bruijn Acked-by: Eric Dumazet Signed-off-by: David S. Miller

ipv6: Allow request socks to contain IPv6 options.

2016-06-27T19:05:28+00:00

If set, these will take precedence over the parent's options during both sending and child creation. If they're not set, the parent's options (if any) will be used. This is to allow the security_inet_conn_request() hook to modify the IPv6 options in just the same way that it already may do for IPv4. Signed-off-by: Huw Davies Signed-off-by: Paul Moore

net: Allow accepted sockets to be bound to l3mdev domain

2015-12-18T19:43:38+00:00

Allow accepted sockets to derive their sk_bound_dev_if setting from the l3mdev domain in which the packets originated. A sysctl setting is added to control the behavior which is similar to sk_mark and sysctl_tcp_fwmark_accept. This effectively allow a process to have a "VRF-global" listen socket, with child sockets bound to the VRF device in which the packet originated. A similar behavior can be achieved using sk_mark, but a solution using marks is incomplete as it does not handle duplicate addresses in different L3 domains/VRFs. Allowing sockets to inherit the sk_bound_dev_if from l3mdev domain provides a complete solution. Signed-off-by: David Ahern Signed-off-by: David S. Miller

xfrm: take care of request sockets

2015-12-07T22:07:33+00:00

TCP SYNACK messages might now be attached to request sockets. XFRM needs to get back to a listener socket. Adds new helpers that might be used elsewhere : sk_to_full_sk() and sk_const_to_full_sk() Note: We also need to add RCU protection for xfrm lookups, now TCP/DCCP have lockless listener processing. This will be addressed in separate patches. Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Reported-by: Dave Jones Signed-off-by: Eric Dumazet Cc: Steffen Klassert Signed-off-by: David S. Miller

net: add skb_to_full_sk() helper and use it in selinux_netlbl_skbuff_setsid()

2015-11-09T01:56:38+00:00

Generalize selinux_skb_sk() added in commit 212cd0895330 ("selinux: fix random read in selinux_ip_postroute_compat()") so that we can use it other contexts. Use it right away in selinux_netlbl_skbuff_setsid() Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: avoid two atomic ops for syncookies

2015-10-05T09:45:27+00:00

inet_reqsk_alloc() is used to allocate a temporary request in order to generate a SYNACK with a cookie. Then later, syncookie validation also uses a temporary request. These paths already took a reference on listener refcount, we can avoid a couple of atomic operations. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: add IP_BIND_ADDRESS_NO_PORT to overcome bind(0) limitations

2015-06-07T06:57:12+00:00

When an application needs to force a source IP on an active TCP socket it has to use bind(IP, port=x). As most applications do not want to deal with already used ports, x is often set to 0, meaning the kernel is in charge to find an available port. But kernel does not know yet if this socket is going to be a listener or be connected. It has very limited choices (no full knowledge of final 4-tuple for a connect()) With limited ephemeral port range (about 32K ports), it is very easy to fill the space. This patch adds a new SOL_IP socket option, asking kernel to ignore the 0 port provided by application in bind(IP, port=0) and only remember the given IP address. The port will be automatically chosen at connect() time, in a way that allows sharing a source port as long as the 4-tuples are unique. This new feature is available for both IPv4 and IPv6 (Thanks Neal) Tested: Wrote a test program and checked its behavior on IPv4 and IPv6. strace(1) shows sequences of bind(IP=127.0.0.2, port=0) followed by connect(). Also getsockname() show that the port is still 0 right after bind() but properly allocated after connect(). socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 5 setsockopt(5, SOL_IP, IP_BIND_ADDRESS_NO_PORT, [1], 4) = 0 bind(5, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("127.0.0.2")}, 16) = 0 getsockname(5, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("127.0.0.2")}, [16]) = 0 connect(5, {sa_family=AF_INET, sin_port=htons(53174), sin_addr=inet_addr("127.0.0.3")}, 16) = 0 getsockname(5, {sa_family=AF_INET, sin_port=htons(38050), sin_addr=inet_addr("127.0.0.2")}, [16]) = 0 IPv6 test : socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = 7 setsockopt(7, SOL_IP, IP_BIND_ADDRESS_NO_PORT, [1], 4) = 0 bind(7, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 0 getsockname(7, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 0 connect(7, {sa_family=AF_INET6, sin6_port=htons(57300), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 0 getsockname(7, {sa_family=AF_INET6, sin6_port=htons(60964), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 0 I was able to bind()/connect() a million concurrent IPv4 sockets, instead of ~32000 before patch. lpaa23:~# ulimit -n 1000010 lpaa23:~# ./bind --connect --num-flows=1000000 & 1000000 sockets lpaa23:~# grep TCP /proc/net/sockstat TCP: inuse 2000063 orphan 0 tw 47 alloc 2000157 mem 66 Check that a given source port is indeed used by many different connections : lpaa23:~# ss -t src :40000 | head -10 State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 0 0 127.0.0.2:40000 127.0.202.33:44983 ESTAB 0 0 127.0.0.2:40000 127.2.27.240:44983 ESTAB 0 0 127.0.0.2:40000 127.2.98.5:44983 ESTAB 0 0 127.0.0.2:40000 127.0.124.196:44983 ESTAB 0 0 127.0.0.2:40000 127.2.139.38:44983 ESTAB 0 0 127.0.0.2:40000 127.1.59.80:44983 ESTAB 0 0 127.0.0.2:40000 127.3.6.228:44983 ESTAB 0 0 127.0.0.2:40000 127.0.38.53:44983 ESTAB 0 0 127.0.0.2:40000 127.1.197.10:44983 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet: fix request sock refcounting

2015-03-18T02:02:29+00:00

While testing last patch series, I found req sock refcounting was wrong. We must set skc_refcnt to 1 for all request socks added in hashes, but also on request sockets created by FastOpen or syncookies. It is tricky because we need to defer this initialization so that future RCU lookups do not try to take a refcount on a not yet fully initialized request socket. Also get rid of ireq_refcnt alias. Signed-off-by: Eric Dumazet Fixes: 13854e5a6046 ("inet: add proper refcounting to request sock") Signed-off-by: David S. Miller

inet: uninline inet_reqsk_alloc()

2015-03-18T02:01:56+00:00

inet_reqsk_alloc() is becoming fat and should not be inlined. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller