kernel/linux.git/net/ipv4/inet_diag.c, branch linux-4.16.y

sock_diag: request _diag module only when the family or proto has been registered

2018-03-12T15:03:42+00:00

Now when using 'ss' in iproute, kernel would try to load all _diag modules, which also causes corresponding family and proto modules to be loaded as well due to module dependencies. Like after running 'ss', sctp, dccp, af_packet (if it works as a module) would be loaded. For example: $ lsmod|grep sctp $ ss $ lsmod|grep sctp sctp_diag 16384 0 sctp 323584 5 sctp_diag inet_diag 24576 4 raw_diag,tcp_diag,sctp_diag,udp_diag libcrc32c 16384 3 nf_conntrack,nf_nat,sctp As these family and proto modules are loaded unintentionally, it could cause some problems, like: - Some debug tools use 'ss' to collect the socket info, which loads all those diag and family and protocol modules. It's noisy for identifying issues. - Users usually expect to drop sctp init packet silently when they have no sense of sctp protocol instead of sending abort back. - It wastes resources (especially with multiple netns), and SCTP module can't be unloaded once it's loaded. ... In short, it's really inappropriate to have these family and proto modules loaded unexpectedly when just doing debugging with inet_diag. This patch is to introduce sock_load_diag_module() where it loads the _diag module only when it's corresponding family or proto has been already registered. Note that we can't just load _diag module without the family or proto loaded, as some symbols used in _diag module are from the family or proto module. v1->v2: - move inet proto check to inet_diag to avoid a compiling err. v2->v3: - define sock_load_diag_module in sock.c and export one symbol only. - improve the changelog. Reported-by: Sabrina Dubroca Acked-by: Marcelo Ricardo Leitner Acked-by: Phil Sutter Acked-by: Sabrina Dubroca Signed-off-by: Xin Long Signed-off-by: David S. Miller

inet_diag: Add equal-operator for ports

2018-01-02T18:54:04+00:00

inet_diag currently provides less/greater than or equal operators for comparing ports when filtering sockets. An equal comparison can be performed by combining the two existing operators, or a user can for example request a port range and then do the final filtering in userspace. However, these approaches both have drawbacks. Implementing equal using LE/GE causes the size and complexity of a filter to grow quickly as the number of ports increase, while it on busy machines would be great if the kernel only returns information about relevant sockets. This patch introduces source and destination port equal operators. INET_DIAG_BC_S_EQ is used to match a source port, INET_DIAG_BC_D_EQ a destination port, and usage is the same as for the existing port operators. I.e., the port to match is stored in the no-member of the next inet_diag_bc_op-struct in the filter. Signed-off-by: Kristian Evensen Signed-off-by: David S. Miller

inet_diag: allow protocols to provide additional data

2017-09-02T01:38:09+00:00

Extend inet_diag_handler to allow individual protocols to report additional data on INET_DIAG_INFO through idiag_get_aux. The size can be dynamic and is computed by idiag_get_aux_size. Signed-off-by: Ivan Delalande Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net: inet: diag: expose sockets cgroup classid

2017-08-18T23:10:50+00:00

This is useful for directly looking up a task based on class id rather than having to scan through all open file descriptors. Signed-off-by: Sasha Levin Signed-off-by: David S. Miller

tcp: remove early retransmit

2017-01-14T03:37:16+00:00

This patch removes the support of RFC5827 early retransmit (i.e., fast recovery on small inflight with <3 dupacks) because it is subsumed by the new RACK loss detection. More specifically when RACK receives DUPACKs, it'll arm a reordering timer to start fast recovery after a quarter of (min)RTT, hence it covers the early retransmit except RACK does not limit itself to specific inflight or dupack numbers. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: add reordering timer in RACK loss detection

2017-01-14T03:37:16+00:00

This patch makes RACK install a reordering timer when it suspects some packets might be lost, but wants to delay the decision a little bit to accomodate reordering. It does not create a new timer but instead repurposes the existing RTO timer, because both are meant to retransmit packets. Specifically it arms a timer ICSK_TIME_REO_TIMEOUT when the RACK timing check fails. The wait time is set to RACK.RTT + RACK.reo_wnd - (NOW - Packet.xmit_time) + fudge This translates to expecting a packet (Packet) should take (RACK.RTT + RACK.reo_wnd + fudge) to deliver after it was sent. When there are multiple packets that need a timer, we use one timer with the maximum timeout. Therefore the timer conservatively uses the maximum window to expire N packets by one timeout, instead of N timeouts to expire N packets sent at different times. The fudge factor is 2 jiffies to ensure when the timer fires, all the suspected packets would exceed the deadline and be marked lost by tcp_rack_detect_loss(). It has to be at least 1 jiffy because the clock may tick between calling icsk_reset_xmit_timer(timeout) and actually hang the timer. The next jiffy is to lower-bound the timeout to 2 jiffies when reo_wnd is < 1ms. When the reordering timer fires (tcp_rack_reo_timeout): If we aren't in Recovery we'll enter fast recovery and force fast retransmit. This is very similar to the early retransmit (RFC5827) except RACK is not constrained to only enter recovery for small outstanding flights. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: no longer hold ehash lock while calling tcp_get_info()

2016-11-09T18:02:27+00:00

We had various problems in the past in tcp_get_info() and used specific synchronization to avoid deadlocks. We would like to add more instrumentation points for TCP, and avoiding grabing socket lock in tcp_getinfo() was too costly. Being able to lock the socket allows to provide consistent set of fields. inet_diag_dump_icsk() can make sure ehash locks are not held any more when tcp_get_info() is called. We can remove syncp added in commit d654976cbf85 ("tcp: fix a potential deadlock in tcp_get_info()"), but we need to use lock_sock_fast() instead of spin_lock_bh() since TCP input path can now be run from process context. Signed-off-by: Eric Dumazet Signed-off-by: Yuchung Cheng Acked-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller

net: ip, diag -- Add diag interface for raw sockets

2016-10-23T23:35:24+00:00

In criu we are actively using diag interface to collect sockets present in the system when dumping applications. And while for unix, tcp, udp[lite], packet, netlink it works as expected, the raw sockets do not have. Thus add it. v2: - add missing sock_put calls in raw_diag_dump_one (by eric.dumazet@) - implement @destroy for diag requests (by dsa@) v3: - add export of raw_abort for IPv6 (by dsa@) - pass net-admin flag into inet_sk_diag_fill due to changes in net-next branch (by dsa@) v4: - use @pad in struct inet_diag_req_v2 for raw socket protocol specification: raw module carries sockets which may have custom protocol passed from socket() syscall and sole @sdiag_protocol is not enough to match underlied ones - start reporting protocol specifed in socket() call when sockets are raw ones for the same reason: user space tools like ss may parse this attribute and use it for socket matching v5 (by eric.dumazet@): - use sock_hold in raw_sock_get instead of atomic_inc, we're holding (raw_v4_hashinfo|raw_v6_hashinfo)->lock when looking up so counter won't be zero here. v6: - use sdiag_raw_protocol() helper which will access @pad structure used for raw sockets protocol specification: we can't simply rename this member without breaking uapi v7: - sine sdiag_raw_protocol() helper is not suitable for uapi lets rather make an alias structure with proper names. __check_inet_diag_req_raw helper will catch if any of structure unintentionally changed. CC: David S. Miller CC: Eric Dumazet CC: David Ahern CC: Alexey Kuznetsov CC: James Morris CC: Hideaki YOSHIFUJI CC: Patrick McHardy CC: Andrey Vagin CC: Stephen Hemminger Signed-off-by: Cyrill Gorcunov Signed-off-by: David S. Miller

tcp: relax listening_hash operations

2016-10-20T15:24:32+00:00

softirq handlers use RCU protection to lookup listeners, and write operations all happen from process context. We do not need to block BH for dump operations. Also SYN_RECV since request sockets are stored in the ehash table : 1) inet_diag_dump_icsk() no longer need to clear cb->args[3] and cb->args[4] that were used as cursors while iterating the old per listener hash table. 2) Also factorize a test : No need to scan listening_hash[] if r->id.idiag_dport is not zero. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: inet: diag: expose the socket mark to privileged processes.

2016-09-08T23:13:09+00:00

This adds the capability for a process that has CAP_NET_ADMIN on a socket to see the socket mark in socket dumps. Commit a52e95abf772 ("net: diag: allow socket bytecode filters to match socket marks") recently gave privileged processes the ability to filter socket dumps based on mark. This patch is complementary: it ensures that the mark is also passed to userspace in the socket's netlink attributes. It is useful for tools like ss which display information about sockets. Tested: https://android-review.googlesource.com/270210 Signed-off-by: Lorenzo Colitti Signed-off-by: David S. Miller