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2020-01-24mptcp: parse and emit MP_CAPABLE option according to v1 specChristoph Paasch
This implements MP_CAPABLE options parsing and writing according to RFC 6824 bis / RFC 8684: MPTCP v1. Local key is sent on syn/ack, and both keys are sent on 3rd ack. MP_CAPABLE messages len are updated accordingly. We need the skbuff to correctly emit the above, so we push the skbuff struct as an argument all the way from tcp code to the relevant mptcp callbacks. When processing incoming MP_CAPABLE + data, build a full blown DSS-like map info, to simplify later processing. On child socket creation, we need to record the remote key, if available. Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24mptcp: Implement MPTCP receive pathMat Martineau
Parses incoming DSS options and populates outgoing MPTCP ACK fields. MPTCP fields are parsed from the TCP option header and placed in an skb extension, allowing the upper MPTCP layer to access MPTCP options after the skb has gone through the TCP stack. The subflow implements its own data_ready() ops, which ensures that the pending data is in sequence - according to MPTCP seq number - dropping out-of-seq skbs. The DATA_READY bit flag is set if this is the case. This allows the MPTCP socket layer to determine if more data is available without having to consult the individual subflows. It additionally validates the current mapping and propagates EoF events to the connection socket. Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Co-developed-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24mptcp: Handle MP_CAPABLE options for outgoing connectionsPeter Krystad
Add hooks to tcp_output.c to add MP_CAPABLE to an outgoing SYN request, to capture the MP_CAPABLE in the received SYN-ACK, to add MP_CAPABLE to the final ACK of the three-way handshake. Use the .sk_rx_dst_set() handler in the subflow proto to capture when the responding SYN-ACK is received and notify the MPTCP connection layer. Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24mptcp: Handle MPTCP TCP optionsPeter Krystad
Add hooks to parse and format the MP_CAPABLE option. This option is handled according to MPTCP version 0 (RFC6824). MPTCP version 1 MP_CAPABLE (RFC6824bis/RFC8684) will be added later in coordination with related code changes. Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Co-developed-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-24mptcp: Add MPTCP socket stubsMat Martineau
Implements the infrastructure for MPTCP sockets. MPTCP sockets open one in-kernel TCP socket per subflow. These subflow sockets are only managed by the MPTCP socket that owns them and are not visible from userspace. This commit allows a userspace program to open an MPTCP socket with: sock = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP); The resulting socket is simply a wrapper around a single regular TCP socket, without any of the MPTCP protocol implemented over the wire. Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-01-22 The following pull-request contains BPF updates for your *net-next* tree. We've added 92 non-merge commits during the last 16 day(s) which contain a total of 320 files changed, 7532 insertions(+), 1448 deletions(-). The main changes are: 1) function by function verification and program extensions from Alexei. 2) massive cleanup of selftests/bpf from Toke and Andrii. 3) batched bpf map operations from Brian and Yonghong. 4) tcp congestion control in bpf from Martin. 5) bulking for non-map xdp_redirect form Toke. 6) bpf_send_signal_thread helper from Yonghong. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-21Merge branch 'master' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next Steffen Klassert says: ==================== pull request (net-next): ipsec-next 2020-01-21 1) Add support for TCP encapsulation of IKE and ESP messages, as defined by RFC 8229. Patchset from Sabrina Dubroca. Please note that there is a merge conflict in: net/unix/af_unix.c between commit: 3c32da19a858 ("unix: Show number of pending scm files of receive queue in fdinfo") from the net-next tree and commit: b50b0580d27b ("net: add queue argument to __skb_wait_for_more_packets and __skb_{,try_}recv_datagram") from the ipsec-next tree. The conflict can be solved as done in linux-next. Please pull or let me know if there are problems. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-21tcp/ipv4: remove AF_INET_FAMILYAlex Shi
After commit 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") the macro isn't used anymore. remove it. Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-19Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
2020-01-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nfDavid S. Miller
Pablo Neira Ayuso says: ==================== Netfilter updates for net The following patchset contains Netfilter fixes for net: 1) Fix use-after-free in ipset bitmap destroy path, from Cong Wang. 2) Missing init netns in entry cleanup path of arp_tables, from Florian Westphal. 3) Fix WARN_ON in set destroy path due to missing cleanup on transaction error. 4) Incorrect netlink sanity check in tunnel, from Florian Westphal. 5) Missing sanity check for erspan version netlink attribute, also from Florian. 6) Remove WARN in nft_request_module() that can be triggered from userspace, from Florian Westphal. 7) Memleak in NFTA_HOOK_DEVS netlink parser, from Dan Carpenter. 8) List poison from commit path for flowtables that are added and deleted in the same batch, from Florian Westphal. 9) Fix NAT ICMP packet corruption, from Eyal Birger. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf 2020-01-15 The following pull-request contains BPF updates for your *net* tree. We've added 12 non-merge commits during the last 9 day(s) which contain a total of 13 files changed, 95 insertions(+), 43 deletions(-). The main changes are: 1) Fix refcount leak for TCP time wait and request sockets for socket lookup related BPF helpers, from Lorenz Bauer. 2) Fix wrong verification of ARSH instruction under ALU32, from Daniel Borkmann. 3) Batch of several sockmap and related TLS fixes found while operating more complex BPF programs with Cilium and OpenSSL, from John Fastabend. 4) Fix sockmap to read psock's ingress_msg queue before regular sk_receive_queue() to avoid purging data upon teardown, from Lingpeng Chen. 5) Fix printing incorrect pointer in bpftool's btf_dump_ptr() in order to properly dump a BPF map's value with BTF, from Martin KaFai Lau. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-15bpf: Sockmap/tls, fix pop data with SK_DROP return codeJohn Fastabend
When user returns SK_DROP we need to reset the number of copied bytes to indicate to the user the bytes were dropped and not sent. If we don't reset the copied arg sendmsg will return as if those bytes were copied giving the user a positive return value. This works as expected today except in the case where the user also pops bytes. In the pop case the sg.size is reduced but we don't correctly account for this when copied bytes is reset. The popped bytes are not accounted for and we return a small positive value potentially confusing the user. The reason this happens is due to a typo where we do the wrong comparison when accounting for pop bytes. In this fix notice the if/else is not needed and that we have a similar problem if we push data except its not visible to the user because if delta is larger the sg.size we return a negative value so it appears as an error regardless. Fixes: 7246d8ed4dcce ("bpf: helper to pop data from messages") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20200111061206.8028-9-john.fastabend@gmail.com
2020-01-15bpf: Sockmap/tls, push write_space updates through ulp updatesJohn Fastabend
When sockmap sock with TLS enabled is removed we cleanup bpf/psock state and call tcp_update_ulp() to push updates to TLS ULP on top. However, we don't push the write_space callback up and instead simply overwrite the op with the psock stored previous op. This may or may not be correct so to ensure we don't overwrite the TLS write space hook pass this field to the ULP and have it fixup the ctx. This completes a previous fix that pushed the ops through to the ULP but at the time missed doing this for write_space, presumably because write_space TLS hook was added around the same time. Fixes: 95fa145479fbc ("bpf: sockmap/tls, close can race with map free") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20200111061206.8028-4-john.fastabend@gmail.com
2020-01-15tcp: fix marked lost packets not being retransmittedPengcheng Yang
When the packet pointed to by retransmit_skb_hint is unlinked by ACK, retransmit_skb_hint will be set to NULL in tcp_clean_rtx_queue(). If packet loss is detected at this time, retransmit_skb_hint will be set to point to the current packet loss in tcp_verify_retransmit_hint(), then the packets that were previously marked lost but not retransmitted due to the restriction of cwnd will be skipped and cannot be retransmitted. To fix this, when retransmit_skb_hint is NULL, retransmit_skb_hint can be reset only after all marked lost packets are retransmitted (retrans_out >= lost_out), otherwise we need to traverse from tcp_rtx_queue_head in tcp_xmit_retransmit_queue(). Packetdrill to demonstrate: // Disable RACK and set max_reordering to keep things simple 0 `sysctl -q net.ipv4.tcp_recovery=0` +0 `sysctl -q net.ipv4.tcp_max_reordering=3` // Establish a connection +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> +0 > S. 0:0(0) ack 1 <...> +.01 < . 1:1(0) ack 1 win 257 +0 accept(3, ..., ...) = 4 // Send 8 data segments +0 write(4, ..., 8000) = 8000 +0 > P. 1:8001(8000) ack 1 // Enter recovery and 1:3001 is marked lost +.01 < . 1:1(0) ack 1 win 257 <sack 3001:4001,nop,nop> +0 < . 1:1(0) ack 1 win 257 <sack 5001:6001 3001:4001,nop,nop> +0 < . 1:1(0) ack 1 win 257 <sack 5001:7001 3001:4001,nop,nop> // Retransmit 1:1001, now retransmit_skb_hint points to 1001:2001 +0 > . 1:1001(1000) ack 1 // 1001:2001 was ACKed causing retransmit_skb_hint to be set to NULL +.01 < . 1:1(0) ack 2001 win 257 <sack 5001:8001 3001:4001,nop,nop> // Now retransmit_skb_hint points to 4001:5001 which is now marked lost // BUG: 2001:3001 was not retransmitted +0 > . 2001:3001(1000) ack 1 Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14ipv4: Add "offload" and "trap" indications to routesIdo Schimmel
When performing L3 offload, routes and nexthops are usually programmed into two different tables in the underlying device. Therefore, the fact that a nexthop resides in hardware does not necessarily mean that all the associated routes also reside in hardware and vice-versa. While the kernel can signal to user space the presence of a nexthop in hardware (via 'RTNH_F_OFFLOAD'), it does not have a corresponding flag for routes. In addition, the fact that a route resides in hardware does not necessarily mean that the traffic is offloaded. For example, unreachable routes (i.e., 'RTN_UNREACHABLE') are programmed to trap packets to the CPU so that the kernel will be able to generate the appropriate ICMP error packet. This patch adds an "offload" and "trap" indications to IPv4 routes, so that users will have better visibility into the offload process. 'struct fib_alias' is extended with two new fields that indicate if the route resides in hardware or not and if it is offloading traffic from the kernel or trapping packets to it. Note that the new fields are added in the 6 bytes hole and therefore the struct still fits in a single cache line [1]. Capable drivers are expected to invoke fib_alias_hw_flags_set() with the route's key in order to set the flags. The indications are dumped to user space via a new flags (i.e., 'RTM_F_OFFLOAD' and 'RTM_F_TRAP') in the 'rtm_flags' field in the ancillary header. v2: * Make use of 'struct fib_rt_info' in fib_alias_hw_flags_set() [1] struct fib_alias { struct hlist_node fa_list; /* 0 16 */ struct fib_info * fa_info; /* 16 8 */ u8 fa_tos; /* 24 1 */ u8 fa_type; /* 25 1 */ u8 fa_state; /* 26 1 */ u8 fa_slen; /* 27 1 */ u32 tb_id; /* 28 4 */ s16 fa_default; /* 32 2 */ u8 offload:1; /* 34: 0 1 */ u8 trap:1; /* 34: 1 1 */ u8 unused:6; /* 34: 2 1 */ /* XXX 5 bytes hole, try to pack */ struct callback_head rcu __attribute__((__aligned__(8))); /* 40 16 */ /* size: 56, cachelines: 1, members: 12 */ /* sum members: 50, holes: 1, sum holes: 5 */ /* sum bitfield members: 8 bits (1 bytes) */ /* forced alignments: 1, forced holes: 1, sum forced holes: 5 */ /* last cacheline: 56 bytes */ } __attribute__((__aligned__(8))); Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: David Ahern <dsahern@gmail.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14ipv4: Encapsulate function arguments in a structIdo Schimmel
fib_dump_info() is used to prepare RTM_{NEW,DEL}ROUTE netlink messages using the passed arguments. Currently, the function takes 11 arguments, 6 of which are attributes of the route being dumped (e.g., prefix, TOS). The next patch will need the function to also dump to user space an indication if the route is present in hardware or not. Instead of passing yet another argument, change the function to take a struct containing the different route attributes. v2: * Name last argument of fib_dump_info() * Move 'struct fib_rt_info' to include/net/ip_fib.h so that it could later be passed to fib_alias_hw_flags_set() Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: David Ahern <dsahern@gmail.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14ipv4: Replace route in list before notifyingIdo Schimmel
Subsequent patches will add an offload / trap indication to routes which will signal if the route is present in hardware or not. After programming the route to the hardware, drivers will have to ask the IPv4 code to set the flags by passing the route's key. In the case of route replace, the new route is notified before it is actually inserted into the FIB alias list. This can prevent simple drivers (e.g., netdevsim) that program the route to the hardware in the same context it is notified in from being able to set the flag. Solve this by first inserting the new route to the list and rollback the operation in case the route was vetoed. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14net: ipv4: use skb_list_walk_safe helper for gso segmentsJason A. Donenfeld
This is a straight-forward conversion case for the new function, keeping the flow of the existing code as intact as possible. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-14net: udp: use skb_list_walk_safe helper for gso segmentsJason A. Donenfeld
This is a straight-forward conversion case for the new function, iterating over the return value from udp_rcv_segment, which actually is a wrapper around skb_gso_segment. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-13netfilter: arp_tables: init netns pointer in xt_tgdtor_param structFlorian Westphal
An earlier commit (1b789577f655060d98d20e, "netfilter: arp_tables: init netns pointer in xt_tgchk_param struct") fixed missing net initialization for arptables, but turns out it was incomplete. We can get a very similar struct net NULL deref during error unwinding: general protection fault: 0000 [#1] PREEMPT SMP KASAN RIP: 0010:xt_rateest_put+0xa1/0x440 net/netfilter/xt_RATEEST.c:77 xt_rateest_tg_destroy+0x72/0xa0 net/netfilter/xt_RATEEST.c:175 cleanup_entry net/ipv4/netfilter/arp_tables.c:509 [inline] translate_table+0x11f4/0x1d80 net/ipv4/netfilter/arp_tables.c:587 do_replace net/ipv4/netfilter/arp_tables.c:981 [inline] do_arpt_set_ctl+0x317/0x650 net/ipv4/netfilter/arp_tables.c:1461 Also init the netns pointer in xt_tgdtor_param struct. Fixes: add67461240c1d ("netfilter: add struct net * to target parameters") Reported-by: syzbot+91bdd8eece0f6629ec8b@syzkaller.appspotmail.com Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2020-01-10ipv4: Detect rollover in specific fib table dumpDavid Ahern
Sven-Haegar reported looping on fib dumps when 255.255.255.255 route has been added to a table. The looping is caused by the key rolling over from FFFFFFFF to 0. When dumping a specific table only, we need a means to detect when the table dump is done. The key and count saved to cb args are both 0 only at the start of the table dump. If key is 0 and count > 0, then we are in the rollover case. Detect and return to avoid looping. This only affects dumps of a specific table; for dumps of all tables (the case prior to the change in the Fixes tag) inet_dump_fib moved the entry counter to the next table and reset the cb args used by fib_table_dump and fn_trie_dump_leaf, so the rollover ffffffff back to 0 did not cause looping with the dumps. Fixes: effe67926624 ("net: Enable kernel side filtering of route dumps") Reported-by: Sven-Haegar Koch <haegar@sdinet.de> Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09tcp: Check for filled TCP option space before SACKMat Martineau
Update the SACK check to work with zero option space available, a case that's possible with MPTCP but not MD5+TS. Maintained only one conditional branch for insufficient SACK space. v1 -> v2: - Moves the check inside the SACK branch by taking recent SACK fix: 9424e2e7ad93 (tcp: md5: fix potential overestimation of TCP option space) in to account, but modifies it to work in MPTCP scenarios beyond the MD5+TS corner case. Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09tcp: Export TCP functions and ops structMat Martineau
MPTCP will make use of tcp_send_mss() and tcp_push() when sending data to specific TCP subflows. tcp_request_sock_ipvX_ops and ipvX_specific will be referenced during TCP subflow creation. Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09tcp: coalesce/collapse must respect MPTCP extensionsMat Martineau
Coalesce and collapse of packets carrying MPTCP extensions is allowed when the newer packet has no extension or the extensions carried by both packets are equal. This allows merging of TSO packet trains and even cross-TSO packets, and does not require any additional action when moving data into existing SKBs. v3 -> v4: - allow collapsing, under mptcp_skb_can_collapse() constraint v5 -> v6: - clarify MPTCP skb extensions must always be cleared at allocation time Co-developed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09tcp, ulp: Add clone operation to tcp_ulp_opsMat Martineau
If ULP is used on a listening socket, icsk_ulp_ops and icsk_ulp_data are copied when the listener is cloned. Sometimes the clone is immediately deleted, which will invoke the release op on the clone and likely corrupt the listening socket's icsk_ulp_data. The clone operation is invoked immediately after the clone is copied and gives the ULP type an opportunity to set up the clone socket and its icsk_ulp_data. The MPTCP ULP clone will silently fallback to plain TCP on allocation failure, so 'clone()' does not need to return an error code. v6 -> v7: - move and rename ulp clone helper to make it inline-friendly v5 -> v6: - clarified MPTCP clone usage in commit message Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09bpf/sockmap: Read psock ingress_msg before sk_receive_queueLingpeng Chen
Right now in tcp_bpf_recvmsg, sock read data first from sk_receive_queue if not empty than psock->ingress_msg otherwise. If a FIN packet arrives and there's also some data in psock->ingress_msg, the data in psock->ingress_msg will be purged. It is always happen when request to a HTTP1.0 server like python SimpleHTTPServer since the server send FIN packet after data is sent out. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: Arika Chen <eaglesora@gmail.com> Suggested-by: Arika Chen <eaglesora@gmail.com> Signed-off-by: Lingpeng Chen <forrest0579@gmail.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200109014833.18951-1-forrest0579@gmail.com
2020-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
The ungrafting from PRIO bug fixes in net, when merged into net-next, merge cleanly but create a build failure. The resolution used here is from Petr Machata. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09bpf: Add BPF_FUNC_tcp_send_ack helperMartin KaFai Lau
Add a helper to send out a tcp-ack. It will be used in the later bpf_dctcp implementation that requires to send out an ack when the CE state changed. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200109004551.3900448-1-kafai@fb.com
2020-01-09bpf: tcp: Support tcp_congestion_ops in bpfMartin KaFai Lau
This patch makes "struct tcp_congestion_ops" to be the first user of BPF STRUCT_OPS. It allows implementing a tcp_congestion_ops in bpf. The BPF implemented tcp_congestion_ops can be used like regular kernel tcp-cc through sysctl and setsockopt. e.g. [root@arch-fb-vm1 bpf]# sysctl -a | egrep congestion net.ipv4.tcp_allowed_congestion_control = reno cubic bpf_cubic net.ipv4.tcp_available_congestion_control = reno bic cubic bpf_cubic net.ipv4.tcp_congestion_control = bpf_cubic There has been attempt to move the TCP CC to the user space (e.g. CCP in TCP). The common arguments are faster turn around, get away from long-tail kernel versions in production...etc, which are legit points. BPF has been the continuous effort to join both kernel and userspace upsides together (e.g. XDP to gain the performance advantage without bypassing the kernel). The recent BPF advancements (in particular BTF-aware verifier, BPF trampoline, BPF CO-RE...) made implementing kernel struct ops (e.g. tcp cc) possible in BPF. It allows a faster turnaround for testing algorithm in the production while leveraging the existing (and continue growing) BPF feature/framework instead of building one specifically for userspace TCP CC. This patch allows write access to a few fields in tcp-sock (in bpf_tcp_ca_btf_struct_access()). The optional "get_info" is unsupported now. It can be added later. One possible way is to output the info with a btf-id to describe the content. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200109003508.3856115-1-kafai@fb.com
2020-01-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nfDavid S. Miller
Pablo Neira Ayuso says: ==================== Netfilter fixes for net The following patchset contains Netfilter fixes for net: 1) Missing netns context in arp_tables, from Florian Westphal. 2) Underflow in flowtable reference counter, from wenxu. 3) Fix incorrect ethernet destination address in flowtable offload, from wenxu. 4) Check for status of neighbour entry, from wenxu. 5) Fix NAT port mangling, from wenxu. 6) Unbind callbacks from destroy path to cleanup hardware properly on flowtable removal. 7) Fix missing casting statistics timestamp, add nf_flowtable_time_stamp and use it. 8) NULL pointer exception when timeout argument is null in conntrack dccp and sctp protocol helpers, from Florian Westphal. 9) Possible nul-dereference in ipset with IPSET_ATTR_LINENO, also from Florian. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-03net: remove the check argument from __skb_gro_checksum_convertLi RongQing
The argument is always ignored, so remove it. Signed-off-by: Li RongQing <lirongqing@baidu.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02tcp: use REXMIT_NEW instead of magic numberMao Wenan
REXMIT_NEW is a macro for "FRTO-style transmit of unsent/new packets", this patch makes it more readable. Signed-off-by: Mao Wenan <maowenan@huawei.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02net: Add device index to tcp_md5sigDavid Ahern
Add support for userspace to specify a device index to limit the scope of an entry via the TCP_MD5SIG_EXT setsockopt. The existing __tcpm_pad is renamed to tcpm_ifindex and the new field is only checked if the new TCP_MD5SIG_FLAG_IFINDEX is set in tcpm_flags. For now, the device index must point to an L3 master device (e.g., VRF). The API and error handling are setup to allow the constraint to be relaxed in the future to any device index. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02tcp: Add l3index to tcp_md5sig_key and md5 functionsDavid Ahern
Add l3index to tcp_md5sig_key to represent the L3 domain of a key, and add l3index to tcp_md5_do_add and tcp_md5_do_del to fill in the key. With the key now based on an l3index, add the new parameter to the lookup functions and consider the l3index when looking for a match. The l3index comes from the skb when processing ingress packets leveraging the helpers created for socket lookups, tcp_v4_sdif and inet_iif (and the v6 variants). When the sdif index is set it means the packet ingressed a device that is part of an L3 domain and inet_iif points to the VRF device. For egress, the L3 domain is determined from the socket binding and sk_bound_dev_if. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02ipv4/tcp: Pass dif and sdif to tcp_v4_inbound_md5_hashDavid Ahern
The original ingress device index is saved to the cb space of the skb and the cb is moved during tcp processing. Since tcp_v4_inbound_md5_hash can be called before and after the cb move, pass dif and sdif to it so the caller can save both prior to the cb move. Both are used by a later patch. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02ipv4/tcp: Use local variable for tcp_md5_addrDavid Ahern
Extract the typecast to (union tcp_md5_addr *) to a local variable rather than the current long, inline declaration with function calls. No functional change intended. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-02tcp: fix "old stuff" D-SACK causing SACK to be treated as D-SACKPengcheng Yang
When we receive a D-SACK, where the sequence number satisfies: undo_marker <= start_seq < end_seq <= prior_snd_una we consider this is a valid D-SACK and tcp_is_sackblock_valid() returns true, then this D-SACK is discarded as "old stuff", but the variable first_sack_index is not marked as negative in tcp_sacktag_write_queue(). If this D-SACK also carries a SACK that needs to be processed (for example, the previous SACK segment was lost), this SACK will be treated as a D-SACK in the following processing of tcp_sacktag_write_queue(), which will eventually lead to incorrect updates of undo_retrans and reordering. Fixes: fd6dad616d4f ("[TCP]: Earlier SACK block verification & simplify access to them") Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Simple overlapping changes in bpf land wrt. bpf_helper_defs.h handling. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-30tcp: Fix highest_sack and highest_sack_seqCambda Zhu
>From commit 50895b9de1d3 ("tcp: highest_sack fix"), the logic about setting tp->highest_sack to the head of the send queue was removed. Of course the logic is error prone, but it is logical. Before we remove the pointer to the highest sack skb and use the seq instead, we need to set tp->highest_sack to NULL when there is no skb after the last sack, and then replace NULL with the real skb when new skb inserted into the rtx queue, because the NULL means the highest sack seq is tp->snd_nxt. If tp->highest_sack is NULL and new data sent, the next ACK with sack option will increase tp->reordering unexpectedly. This patch sets tp->highest_sack to the tail of the rtx queue if it's NULL and new data is sent. The patch keeps the rule that the highest_sack can only be maintained by sack processing, except for this only case. Fixes: 50895b9de1d3 ("tcp: highest_sack fix") Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-30tcp_cubic: refactor code to perform a divide only when neededEric Dumazet
Neal Cardwell suggested to not change ca->delay_min and apply the ack delay cushion only when Hystart ACK train is still under consideration. This should avoid a 64bit divide unless needed. Tested: 40Gbit(mlx4) testbed (with sch_fq as packet scheduler) $ echo -n 'file tcp_cubic.c +p' >/sys/kernel/debug/dynamic_debug/control $ nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 14815 16280 15293 15563 11574 15145 14789 18548 16972 12520 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 1396 0.0 $ dmesg | tail -10 [ 4873.951350] hystart_ack_train (116 > 93) delay_min 24 (+ ack_delay 69) cwnd 80 [ 4875.155379] hystart_ack_train (55 > 50) delay_min 21 (+ ack_delay 29) cwnd 160 [ 4876.333921] hystart_ack_train (69 > 62) delay_min 23 (+ ack_delay 39) cwnd 130 [ 4877.519037] hystart_ack_train (69 > 60) delay_min 22 (+ ack_delay 38) cwnd 130 [ 4878.701559] hystart_ack_train (87 > 63) delay_min 24 (+ ack_delay 39) cwnd 160 [ 4879.844597] hystart_ack_train (93 > 50) delay_min 21 (+ ack_delay 29) cwnd 216 [ 4880.956650] hystart_ack_train (74 > 67) delay_min 20 (+ ack_delay 47) cwnd 108 [ 4882.098500] hystart_ack_train (61 > 57) delay_min 23 (+ ack_delay 34) cwnd 130 [ 4883.262056] hystart_ack_train (72 > 67) delay_min 21 (+ ack_delay 46) cwnd 130 [ 4884.418760] hystart_ack_train (74 > 67) delay_min 29 (+ ack_delay 38) cwnd 152 10Gbit(bnx2x) testbed (with sch_fq as packet scheduler) $ echo -n 'file tcp_cubic.c +p' >/sys/kernel/debug/dynamic_debug/control $ nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpk52 -l -4000000; done;nstat|egrep "Hystart" 7050 7065 7100 6900 7202 7263 7189 6869 7463 7034 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 3199 0.0 $ dmesg | tail -10 [ 176.920012] hystart_ack_train (161 > 141) delay_min 83 (+ ack_delay 58) cwnd 264 [ 179.144645] hystart_ack_train (164 > 159) delay_min 120 (+ ack_delay 39) cwnd 444 [ 181.354527] hystart_ack_train (214 > 168) delay_min 125 (+ ack_delay 43) cwnd 436 [ 183.539565] hystart_ack_train (170 > 147) delay_min 96 (+ ack_delay 51) cwnd 326 [ 185.727309] hystart_ack_train (177 > 160) delay_min 61 (+ ack_delay 99) cwnd 128 [ 187.947142] hystart_ack_train (184 > 167) delay_min 123 (+ ack_delay 44) cwnd 367 [ 190.166680] hystart_ack_train (230 > 153) delay_min 116 (+ ack_delay 37) cwnd 444 [ 192.327285] hystart_ack_train (210 > 206) delay_min 86 (+ ack_delay 120) cwnd 152 [ 194.511392] hystart_ack_train (173 > 151) delay_min 94 (+ ack_delay 57) cwnd 239 [ 196.736023] hystart_ack_train (149 > 146) delay_min 105 (+ ack_delay 41) cwnd 399 Fixes: 42f3a8aaae66 ("tcp_cubic: tweak Hystart detection for short RTT flows") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Neal Cardwell <ncardwell@google.com> Link: https://www.spinics.net/lists/netdev/msg621886.html Link: https://www.spinics.net/lists/netdev/msg621797.html Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-30netfilter: arp_tables: init netns pointer in xt_tgchk_param structFlorian Westphal
We get crash when the targets checkentry function tries to make use of the network namespace pointer for arptables. When the net pointer got added back in 2010, only ip/ip6/ebtables were changed to initialize it, so arptables has this set to NULL. This isn't a problem for normal arptables because no existing arptables target has a checkentry function that makes use of par->net. However, direct users of the setsockopt interface can provide any target they want as long as its registered for ARP or UNPSEC protocols. syzkaller managed to send a semi-valid arptables rule for RATEEST target which is enough to trigger NULL deref: kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN RIP: xt_rateest_tg_checkentry+0x11d/0xb40 net/netfilter/xt_RATEEST.c:109 [..] xt_check_target+0x283/0x690 net/netfilter/x_tables.c:1019 check_target net/ipv4/netfilter/arp_tables.c:399 [inline] find_check_entry net/ipv4/netfilter/arp_tables.c:422 [inline] translate_table+0x1005/0x1d70 net/ipv4/netfilter/arp_tables.c:572 do_replace net/ipv4/netfilter/arp_tables.c:977 [inline] do_arpt_set_ctl+0x310/0x640 net/ipv4/netfilter/arp_tables.c:1456 Fixes: add67461240c1d ("netfilter: add struct net * to target parameters") Reported-by: syzbot+d7358a458d8a81aee898@syzkaller.appspotmail.com Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2019-12-27tcp_cubic: make Hystart aware of pacingEric Dumazet
For years we disabled Hystart ACK train detection at Google because it was fooled by TCP pacing. ACK train detection uses a simple heuristic, detecting if we receive ACK past half the RTT, to exit slow start before hitting the bottleneck and experience massive drops. But pacing by design might delay packets up to RTT/2, so we need to tweak the Hystart logic to be aware of this extra delay. Tested: Added a 100 usec delay at receiver. Before: nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 9117 7057 9553 8300 7030 6849 9533 10126 6876 8473 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 1230 0.0 After : nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 9845 10103 10866 11096 11936 11487 11773 12188 11066 11894 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 6462 0.0 Disabling Hystart ACK Train detection gives similar numbers echo 2 >/sys/module/tcp_cubic/parameters/hystart_detect nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 11173 10954 12455 10627 11578 11583 11222 10880 10665 11366 Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-27tcp_cubic: tweak Hystart detection for short RTT flowsEric Dumazet
After switching ca->delay_min to usec resolution, we exit slow start prematurely for very low RTT flows, setting snd_ssthresh to 20. The reason is that delay_min is fed with RTT of small packet trains. Then as cwnd is increased, TCP sends bigger TSO packets. LRO/GRO aggregation and/or interrupt mitigation strategies on receiver tend to inflate RTT samples. Fix this by adding to delay_min the expected delay of two TSO packets, given current pacing rate. Tested: Sender uses pfifo_fast qdisc Before : $ nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 11348 11707 11562 11428 11773 11534 9878 11693 10597 10968 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 200 0.0 After : $ nstat -n;for f in {1..10}; do ./super_netperf 1 -H lpaa24 -l -4000000; done;nstat|egrep "Hystart" 14877 14517 15797 18466 17376 14833 17558 17933 16039 18059 TcpExtTCPHystartTrainDetect 10 0.0 TcpExtTCPHystartTrainCwnd 1670 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-27tcp_cubic: switch bictcp_clock() to usec resolutionEric Dumazet
Current 1ms clock feeds ca->round_start, ca->delay_min, ca->last_ack. This is quite problematic for data-center flows, where delay_min is way below 1 ms. This means Hystart Train detection triggers every time jiffies value is updated, since "((s32)(now - ca->round_start) > ca->delay_min >> 4)" expression becomes true. This kind of random behavior can be solved by reusing the existing usec timestamp that TCP keeps in tp->tcp_mstamp Note that a followup patch will tweak things a bit, because during slow start, GRO aggregation on receivers naturally increases the RTT as TSO packets gradually come to ~64KB size. To recap, right after this patch CUBIC Hystart train detection is more aggressive, since short RTT flows might exit slow start at cwnd = 20, instead of being possibly unbounded. Following patch will address this problem. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-27tcp_cubic: remove one conditional from hystart_update()Eric Dumazet
If we initialize ca->curr_rtt to ~0U, we do not need to test for zero value in hystart_update() We only read ca->curr_rtt if at least HYSTART_MIN_SAMPLES have been processed, and thus ca->curr_rtt will have a sane value. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-27tcp_cubic: optimize hystart_update()Eric Dumazet
We do not care which bit in ca->found is set. We avoid accessing hystart and hystart_detect unless really needed, possibly avoiding one cache line miss. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24vti: do not confirm neighbor when do pmtu updateHangbin Liu
When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. Although vti and vti6 are immune to this problem because they are IFF_NOARP interfaces, as Guillaume pointed. There is still no sense to confirm neighbour here. v5: Update commit description. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Reviewed-by: Guillaume Nault <gnault@redhat.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24tunnel: do not confirm neighbor when do pmtu updateHangbin Liu
When do tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. v5: No Change. v4: Update commit description v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Fixes: 0dec879f636f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP") Reviewed-by: Guillaume Nault <gnault@redhat.com> Tested-by: Guillaume Nault <gnault@redhat.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24net: add bool confirm_neigh parameter for dst_ops.update_pmtuHangbin Liu
The MTU update code is supposed to be invoked in response to real networking events that update the PMTU. In IPv6 PMTU update function __ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor confirmed time. But for tunnel code, it will call pmtu before xmit, like: - tnl_update_pmtu() - skb_dst_update_pmtu() - ip6_rt_update_pmtu() - __ip6_rt_update_pmtu() - dst_confirm_neigh() If the tunnel remote dst mac address changed and we still do the neigh confirm, we will not be able to update neigh cache and ping6 remote will failed. So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we should not be invoking dst_confirm_neigh() as we have no evidence of successful two-way communication at this point. On the other hand it is also important to keep the neigh reachability fresh for TCP flows, so we cannot remove this dst_confirm_neigh() call. To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu to choose whether we should do neigh update or not. I will add the parameter in this patch and set all the callers to true to comply with the previous way, and fix the tunnel code one by one on later patches. v5: No change. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Suggested-by: David Miller <davem@davemloft.net> Reviewed-by: Guillaume Nault <gnault@redhat.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24udp: fix integer overflow while computing available space in sk_rcvbufAntonio Messina
When the size of the receive buffer for a socket is close to 2^31 when computing if we have enough space in the buffer to copy a packet from the queue to the buffer we might hit an integer overflow. When an user set net.core.rmem_default to a value close to 2^31 UDP packets are dropped because of this overflow. This can be visible, for instance, with failure to resolve hostnames. This can be fixed by casting sk_rcvbuf (which is an int) to unsigned int, similarly to how it is done in TCP. Signed-off-by: Antonio Messina <amessina@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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