kernel/linux.git/include/net/lwtunnel.h, branch linux-7.0.y

net: dst: annotate data-races around dst->output

2025-07-02T21:32:30+00:00

dst_dev_put() can overwrite dst->output while other cpus might read this field (for instance from dst_output()) Add READ_ONCE()/WRITE_ONCE() annotations to suppress potential issues. We will likely need RCU protection in the future. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-6-edumazet@google.com Signed-off-by: Jakub Kicinski

net: dst: annotate data-races around dst->input

2025-07-02T21:32:29+00:00

dst_dev_put() can overwrite dst->input while other cpus might read this field (for instance from dst_input()) Add READ_ONCE()/WRITE_ONCE() annotations to suppress potential issues. We will likely need full RCU protection later. Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com Signed-off-by: Jakub Kicinski

inet: Remove rtnl_is_held arg of lwtunnel_valid_encap_type(_attr)?().

2025-05-21T02:18:24+00:00

Commit f130a0cc1b4f ("inet: fix lwtunnel_valid_encap_type() lock imbalance") added the rtnl_is_held argument as a temporary fix while I'm converting nexthop and IPv6 routing table to per-netns RTNL or RCU. Now all callers of lwtunnel_valid_encap_type() do not hold RTNL. Let's remove the argument. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250516022759.44392-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

inet: fix lwtunnel_valid_encap_type() lock imbalance

2025-03-06T03:16:56+00:00

After blamed commit rtm_to_fib_config() now calls lwtunnel_valid_encap_type{_attr}() without RTNL held, triggering an unlock balance in __rtnl_unlock, as reported by syzbot [1] IPv6 and rtm_to_nh_config() are not yet converted. Add a temporary @rtnl_is_held parameter to lwtunnel_valid_encap_type() and lwtunnel_valid_encap_type_attr(). While we are at it replace the two rcu_dereference() in lwtunnel_valid_encap_type() with more appropriate rcu_access_pointer(). [1] syz-executor245/5836 is trying to release lock (rtnl_mutex) at: [] __rtnl_unlock+0x6c/0xf0 net/core/rtnetlink.c:142 but there are no more locks to release! other info that might help us debug this: no locks held by syz-executor245/5836. stack backtrace: CPU: 0 UID: 0 PID: 5836 Comm: syz-executor245 Not tainted 6.14.0-rc4-syzkaller-00873-g3424291dd242 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_unlock_imbalance_bug+0x25b/0x2d0 kernel/locking/lockdep.c:5289 __lock_release kernel/locking/lockdep.c:5518 [inline] lock_release+0x47e/0xa30 kernel/locking/lockdep.c:5872 __mutex_unlock_slowpath+0xec/0x800 kernel/locking/mutex.c:891 __rtnl_unlock+0x6c/0xf0 net/core/rtnetlink.c:142 lwtunnel_valid_encap_type+0x38a/0x5f0 net/core/lwtunnel.c:169 lwtunnel_valid_encap_type_attr+0x113/0x270 net/core/lwtunnel.c:209 rtm_to_fib_config+0x949/0x14e0 net/ipv4/fib_frontend.c:808 inet_rtm_newroute+0xf6/0x2a0 net/ipv4/fib_frontend.c:917 rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919 netlink_rcv_skb+0x206/0x480 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:709 [inline] Fixes: 1dd2af7963e9 ("ipv4: fib: Convert RTM_NEWROUTE and RTM_DELROUTE to per-netns RTNL.") Reported-by: syzbot+3f18ef0f7df107a3f6a0@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67c6f87a.050a0220.38b91b.0147.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250304125918.2763514-1-edumazet@google.com Signed-off-by: Jakub Kicinski

lwt: Check LWTUNNEL_XMIT_CONTINUE strictly

2023-08-18T14:05:26+00:00

LWTUNNEL_XMIT_CONTINUE is implicitly assumed in ip(6)_finish_output2, such that any positive return value from a xmit hook could cause unexpected continue behavior, despite that related skb may have been freed. This could be error-prone for future xmit hook ops. One of the possible errors is to return statuses of dst_output directly. To make the code safer, redefine LWTUNNEL_XMIT_CONTINUE value to distinguish from dst_output statuses and check the continue condition explicitly. Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure") Suggested-by: Dan Carpenter Signed-off-by: Yan Zhai Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/96b939b85eda00e8df4f7c080f770970a4c5f698.1692326837.git.yan@cloudflare.com

netfilter: add netfilter hooks to SRv6 data plane

2021-08-29T23:51:36+00:00

This patch introduces netfilter hooks for solving the problem that conntrack couldn't record both inner flows and outer flows. This patch also introduces a new sysctl toggle for enabling lightweight tunnel netfilter hooks. Signed-off-by: Ryoga Saito Signed-off-by: Pablo Neira Ayuso

net: add net available in build_state

2020-03-30T05:30:57+00:00

The build_state callback of lwtunnel doesn't contain the net namespace structure yet. This patch will add it so we can check on specific address configuration at creation time of rpl source routes. Signed-off-by: Alexander Aring Signed-off-by: David S. Miller

net: lwtunnel: Replace zero-length array with flexible-array member

2020-03-01T05:52:20+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller

lwtunnel: Pass encap and encap type attributes to lwtunnel_fill_encap

2019-04-24T02:42:29+00:00

Currently, lwtunnel_fill_encap hardcodes the encap and encap type attributes as RTA_ENCAP and RTA_ENCAP_TYPE, respectively. The nexthop objects want to re-use this code but the encap attributes passed to userspace as NHA_ENCAP and NHA_ENCAP_TYPE. Since that is the only difference, change lwtunnel_fill_encap to take the attribute type as an input. Signed-off-by: David Ahern Signed-off-by: David S. Miller

bpf: implement BPF_LWT_ENCAP_IP mode in bpf_lwt_push_encap

2019-02-14T02:27:55+00:00

Implement BPF_LWT_ENCAP_IP mode in bpf_lwt_push_encap BPF helper. It enables BPF programs (specifically, BPF_PROG_TYPE_LWT_IN and BPF_PROG_TYPE_LWT_XMIT prog types) to add IP encapsulation headers to packets (e.g. IP/GRE, GUE, IPIP). This is useful when thousands of different short-lived flows should be encapped, each with different and dynamically determined destination. Although lwtunnels can be used in some of these scenarios, the ability to dynamically generate encap headers adds more flexibility, e.g. when routing depends on the state of the host (reflected in global bpf maps). v7 changes: - added a call skb_clear_hash(); - removed calls to skb_set_transport_header(); - refuse to encap GSO-enabled packets. v8 changes: - fix build errors when LWT is not enabled. Note: the next patch in the patchset with deal with GSO-enabled packets, which are currently rejected at encapping attempt. Signed-off-by: Peter Oskolkov Signed-off-by: Alexei Starovoitov