04 Aug, 2020
1 commit
-
Refactor the function seg6_lwt_headroom out of the seg6_iptunnel.h uapi
header, because it is only used in seg6_iptunnel.c. Moreover, it is only
used in the kernel code, as indicated by the "#ifdef __KERNEL__".Suggested-by: David Miller
Signed-off-by: Ioana-Ruxandra Stăncioi
Signed-off-by: David S. Miller
05 Jun, 2020
1 commit
-
The seg6_validate_srh() is used to validate SRH for three cases:
case1: SRH of data-plane SRv6 packets to be processed by the Linux kernel.
Case2: SRH of the netlink message received from user-space (iproute2)
Case3: SRH injected into packets through setsockoptIn case1, the SRH can be encoded in the Reduced way (i.e., first SID is
carried in DA only and not represented as SID in the SRH) and the
seg6_validate_srh() now handles this case correctly.In case2 and case3, the SRH shouldn’t be encoded in the Reduced way
otherwise we lose the first segment (i.e., the first hop).The current implementation of the seg6_validate_srh() allow SRH of case2
and case3 to be encoded in the Reduced way. This leads a slab-out-of-bounds
problem.This patch verifies SRH of case1, case2 and case3. Allowing case1 to be
reduced while preventing SRH of case2 and case3 from being reduced .Reported-by: syzbot+e8c028b62439eac42073@syzkaller.appspotmail.com
Reported-by: YueHaibing
Fixes: 0cb7498f234e ("seg6: fix SRH processing to comply with RFC8754")
Signed-off-by: Ahmed Abdelsalam
Signed-off-by: David S. Miller
30 Mar, 2020
1 commit
-
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
13 Mar, 2020
1 commit
-
Minor overlapping changes, nothing serious.
Signed-off-by: David S. Miller
12 Mar, 2020
1 commit
-
The Internet Assigned Numbers Authority (IANA) has recently assigned
a protocol number value of 143 for Ethernet [1].Before this assignment, encapsulation mechanisms such as Segment Routing
used the IPv6-NoNxt protocol number (59) to indicate that the encapsulated
payload is an Ethernet frame.In this patch, we add the definition of the Ethernet protocol number to the
kernel headers and update the SRv6 L2 tunnels to use it.[1] https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
Signed-off-by: Paolo Lungaroni
Reviewed-by: Andrea Mayer
Acked-by: Ahmed Abdelsalam
Signed-off-by: David S. Miller
29 Feb, 2020
1 commit
-
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
31 May, 2019
1 commit
-
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later versionextracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman
28 Apr, 2019
1 commit
-
We currently have two levels of strict validation:
1) liberal (default)
- undefined (type >= max) & NLA_UNSPEC attributes accepted
- attribute length >= expected accepted
- garbage at end of message accepted
2) strict (opt-in)
- NLA_UNSPEC attributes accepted
- attribute length >= expected acceptedSplit out parsing strictness into four different options:
* TRAILING - check that there's no trailing data after parsing
attributes (in message or nested)
* MAXTYPE - reject attrs > max known type
* UNSPEC - reject attributes with NLA_UNSPEC policy entries
* STRICT_ATTRS - strictly validate attribute sizeThe default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.We end up with the following renames:
* nla_parse -> nla_parse_deprecated
* nla_parse_strict -> nla_parse_deprecated_strict
* nlmsg_parse -> nlmsg_parse_deprecated
* nlmsg_parse_strict -> nlmsg_parse_deprecated_strict
* nla_parse_nested -> nla_parse_nested_deprecated
* nla_validate_nested -> nla_validate_nested_deprecatedUsing spatch, of course:
@@
expression TB, MAX, HEAD, LEN, POL, EXT;
@@
-nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
+nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)@@
expression NLH, HDRLEN, TB, MAX, POL, EXT;
@@
-nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
+nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)@@
expression TB, MAX, NLA, POL, EXT;
@@
-nla_parse_nested(TB, MAX, NLA, POL, EXT)
+nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)@@
expression START, MAX, POL, EXT;
@@
-nla_validate_nested(START, MAX, POL, EXT)
+nla_validate_nested_deprecated(START, MAX, POL, EXT)@@
expression NLH, HDRLEN, MAX, POL, EXT;
@@
-nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
+nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.In effect then, this adds fully strict validation for any new command.
Signed-off-by: Johannes Berg
Signed-off-by: David S. Miller
31 Jan, 2019
1 commit
-
skb->cb may contain data from previous layers (in an observed case
IPv4 with L3 Master Device). In the observed scenario, the data in
IPCB(skb)->frags was misinterpreted as IP6CB(skb)->frag_max_size,
eventually caused an unexpected IPv6 fragmentation in ip6_fragment()
through ip6_finish_output().This patch clears IP6CB(skb), which potentially contains garbage data,
on the SRH ip4ip6 encapsulation.Fixes: 32d99d0b6702 ("ipv6: sr: add support for ip4ip6 encapsulation")
Signed-off-by: Yohei Kanemaru
Signed-off-by: David S. Miller
08 Dec, 2018
1 commit
-
In 'seg6_output', stack variable 'struct flowi6 fl6' was missing
initialization.Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: Shmulik Ladkani
Signed-off-by: David S. Miller
19 Jul, 2018
1 commit
-
The rol32 call is currently rotating hash but the rol'd value is
being discarded. I believe the current code is incorrect and hash
should be assigned the rotated value returned from rol32.Detected by CoverityScan, CID#1468411 ("Useless call")
Fixes: b5facfdba14c ("ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode")
Signed-off-by: Colin Ian King
Acked-by: dlebrun@google.com
Signed-off-by: David S. Miller
03 Jun, 2018
1 commit
-
Filling in the padding slot in the bpf structure as a bug fix in 'ne'
overlapped with actually using that padding area for something in
'net-next'.Signed-off-by: David S. Miller
29 May, 2018
1 commit
-
seg6_do_srh_encap and seg6_do_srh_inline can possibly do an
out-of-bounds access when adding the SRH to the packet. This no longer
happen when expanding the skb not only by the size of the SRH (+
outer IPv6 header), but also by skb->mac_len.[ 53.793056] BUG: KASAN: use-after-free in seg6_do_srh_encap+0x284/0x620
[ 53.794564] Write of size 14 at addr ffff88011975ecfa by task ping/674[ 53.796665] CPU: 0 PID: 674 Comm: ping Not tainted 4.17.0-rc3-ARCH+ #90
[ 53.796670] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.11.0-20171110_100015-anatol 04/01/2014
[ 53.796673] Call Trace:
[ 53.796679]
[ 53.796689] dump_stack+0x71/0xab
[ 53.796700] print_address_description+0x6a/0x270
[ 53.796707] kasan_report+0x258/0x380
[ 53.796715] ? seg6_do_srh_encap+0x284/0x620
[ 53.796722] memmove+0x34/0x50
[ 53.796730] seg6_do_srh_encap+0x284/0x620
[ 53.796741] ? seg6_do_srh+0x29b/0x360
[ 53.796747] seg6_do_srh+0x29b/0x360
[ 53.796756] seg6_input+0x2e/0x2e0
[ 53.796765] lwtunnel_input+0x93/0xd0
[ 53.796774] ipv6_rcv+0x690/0x920
[ 53.796783] ? ip6_input+0x170/0x170
[ 53.796791] ? eth_gro_receive+0x2d0/0x2d0
[ 53.796800] ? ip6_input+0x170/0x170
[ 53.796809] __netif_receive_skb_core+0xcc0/0x13f0
[ 53.796820] ? netdev_info+0x110/0x110
[ 53.796827] ? napi_complete_done+0xb6/0x170
[ 53.796834] ? e1000_clean+0x6da/0xf70
[ 53.796845] ? process_backlog+0x129/0x2a0
[ 53.796853] process_backlog+0x129/0x2a0
[ 53.796862] net_rx_action+0x211/0x5c0
[ 53.796870] ? napi_complete_done+0x170/0x170
[ 53.796887] ? run_rebalance_domains+0x11f/0x150
[ 53.796891] __do_softirq+0x10e/0x39e
[ 53.796894] do_softirq_own_stack+0x2a/0x40
[ 53.796895]
[ 53.796898] do_softirq.part.16+0x54/0x60
[ 53.796900] __local_bh_enable_ip+0x5b/0x60
[ 53.796903] ip6_finish_output2+0x416/0x9f0
[ 53.796906] ? ip6_dst_lookup_flow+0x110/0x110
[ 53.796909] ? ip6_sk_dst_lookup_flow+0x390/0x390
[ 53.796911] ? __rcu_read_unlock+0x66/0x80
[ 53.796913] ? ip6_mtu+0x44/0xf0
[ 53.796916] ? ip6_output+0xfc/0x220
[ 53.796918] ip6_output+0xfc/0x220
[ 53.796921] ? ip6_finish_output+0x2b0/0x2b0
[ 53.796923] ? memcpy+0x34/0x50
[ 53.796926] ip6_send_skb+0x43/0xc0
[ 53.796929] rawv6_sendmsg+0x1216/0x1530
[ 53.796932] ? __orc_find+0x6b/0xc0
[ 53.796934] ? rawv6_rcv_skb+0x160/0x160
[ 53.796937] ? __rcu_read_unlock+0x66/0x80
[ 53.796939] ? __rcu_read_unlock+0x66/0x80
[ 53.796942] ? is_bpf_text_address+0x1e/0x30
[ 53.796944] ? kernel_text_address+0xec/0x100
[ 53.796946] ? __kernel_text_address+0xe/0x30
[ 53.796948] ? unwind_get_return_address+0x2f/0x50
[ 53.796950] ? __save_stack_trace+0x92/0x100
[ 53.796954] ? save_stack+0x89/0xb0
[ 53.796956] ? kasan_kmalloc+0xa0/0xd0
[ 53.796958] ? kmem_cache_alloc+0xd2/0x1f0
[ 53.796961] ? prepare_creds+0x23/0x160
[ 53.796963] ? __x64_sys_capset+0x252/0x3e0
[ 53.796966] ? do_syscall_64+0x69/0x160
[ 53.796968] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 53.796971] ? __alloc_pages_nodemask+0x170/0x380
[ 53.796973] ? __alloc_pages_slowpath+0x12c0/0x12c0
[ 53.796977] ? tty_vhangup+0x20/0x20
[ 53.796979] ? policy_nodemask+0x1a/0x90
[ 53.796982] ? __mod_node_page_state+0x8d/0xa0
[ 53.796986] ? __check_object_size+0xe7/0x240
[ 53.796989] ? __sys_sendto+0x229/0x290
[ 53.796991] ? rawv6_rcv_skb+0x160/0x160
[ 53.796993] __sys_sendto+0x229/0x290
[ 53.796996] ? __ia32_sys_getpeername+0x50/0x50
[ 53.796999] ? commit_creds+0x2de/0x520
[ 53.797002] ? security_capset+0x57/0x70
[ 53.797004] ? __x64_sys_capset+0x29f/0x3e0
[ 53.797007] ? __x64_sys_rt_sigsuspend+0xe0/0xe0
[ 53.797011] ? __do_page_fault+0x664/0x770
[ 53.797014] __x64_sys_sendto+0x74/0x90
[ 53.797017] do_syscall_64+0x69/0x160
[ 53.797019] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 53.797022] RIP: 0033:0x7f43b7a6714a
[ 53.797023] RSP: 002b:00007ffd891bd368 EFLAGS: 00000246 ORIG_RAX:
000000000000002c
[ 53.797026] RAX: ffffffffffffffda RBX: 00000000006129c0 RCX: 00007f43b7a6714a
[ 53.797028] RDX: 0000000000000040 RSI: 00000000006129c0 RDI: 0000000000000004
[ 53.797029] RBP: 00007ffd891be640 R08: 0000000000610940 R09: 000000000000001c
[ 53.797030] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040
[ 53.797032] R13: 000000000060e6a0 R14: 0000000000008004 R15: 000000000040b661[ 53.797171] Allocated by task 642:
[ 53.797460] kasan_kmalloc+0xa0/0xd0
[ 53.797463] kmem_cache_alloc+0xd2/0x1f0
[ 53.797465] getname_flags+0x40/0x210
[ 53.797467] user_path_at_empty+0x1d/0x40
[ 53.797469] do_faccessat+0x12a/0x320
[ 53.797471] do_syscall_64+0x69/0x160
[ 53.797473] entry_SYSCALL_64_after_hwframe+0x44/0xa9[ 53.797607] Freed by task 642:
[ 53.797869] __kasan_slab_free+0x130/0x180
[ 53.797871] kmem_cache_free+0xa8/0x230
[ 53.797872] filename_lookup+0x15b/0x230
[ 53.797874] do_faccessat+0x12a/0x320
[ 53.797876] do_syscall_64+0x69/0x160
[ 53.797878] entry_SYSCALL_64_after_hwframe+0x44/0xa9[ 53.798014] The buggy address belongs to the object at ffff88011975e600
which belongs to the cache names_cache of size 4096
[ 53.799043] The buggy address is located 1786 bytes inside of
4096-byte region [ffff88011975e600, ffff88011975f600)
[ 53.800013] The buggy address belongs to the page:
[ 53.800414] page:ffffea000465d600 count:1 mapcount:0
mapping:0000000000000000 index:0x0 compound_mapcount: 0
[ 53.801259] flags: 0x17fff0000008100(slab|head)
[ 53.801640] raw: 017fff0000008100 0000000000000000 0000000000000000
0000000100070007
[ 53.803147] raw: dead000000000100 dead000000000200 ffff88011b185a40
0000000000000000
[ 53.803787] page dumped because: kasan: bad access detected[ 53.804384] Memory state around the buggy address:
[ 53.804788] ffff88011975eb80: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 53.805384] ffff88011975ec00: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 53.805979] >ffff88011975ec80: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 53.806577] ^
[ 53.807165] ffff88011975ed00: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 53.807762] ffff88011975ed80: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 53.808356] ==================================================================
[ 53.808949] Disabling lock debugging due to kernel taintFixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: David Lebrun
Signed-off-by: Mathieu Xhonneux
Signed-off-by: David S. Miller
01 May, 2018
1 commit
-
The seg6_make_flowlabel() is used by seg6_do_srh_encap() to compute the
flowlabel from a given skb. It relies on skb_get_hash() which eventually
calls __skb_flow_dissect() to extract the flow_keys struct values from
the skb.In case of IPv4 traffic, calling seg6_make_flowlabel() after skb_push(),
skb_reset_network_header(), and skb_mac_header_rebuild() will results in
flow_keys struct of all key values set to zero.This patch calls seg6_make_flowlabel() before resetting the headers of skb
to get the right key values.Extracted Key values are based on the type inner packet as follows:
1) IPv6 traffic: src_IP, dst_IP, L4 proto, and flowlabel of inner packet.
2) IPv4 traffic: src_IP, dst_IP, L4 proto, src_port, and dst_port
3) L2 traffic: depends on what kind of traffic carried into the L2
frame. IPv6 and IPv4 traffic works as discussed 1) and 2)Here a hex_dump of struct flow_keys for IPv4 and IPv6 traffic
10.100.1.100: 47302 > 30.0.0.2: 5001
00000000: 14 00 02 00 00 00 00 00 08 00 11 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 13 89 b8 c6 1e 00 00 02
00000020: 0a 64 01 64fc00:a1:a > b2::2
00000000: 28 00 03 00 00 00 00 00 86 dd 11 00 99 f9 02 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 b2 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 02 fc 00 00 a1
00000030: 00 00 00 00 00 00 00 00 00 00 00 0aSigned-off-by: Ahmed Abdelsalam
Signed-off-by: David S. Miller
26 Apr, 2018
1 commit
-
ECMP (equal-cost multipath) hashes are typically computed on the packets'
5-tuple(src IP, dst IP, src port, dst port, L4 proto).For encapsulated packets, the L4 data is not readily available and ECMP
hashing will often revert to (src IP, dst IP). This will lead to traffic
polarization on a single ECMP path, causing congestion and waste of network
capacity.In IPv6, the 20-bit flow label field is also used as part of the ECMP hash.
In the lack of L4 data, the hashing will be on (src IP, dst IP, flow
label). Having a non-zero flow label is thus important for proper traffic
load balancing when L4 data is unavailable (i.e., when packets are
encapsulated).Currently, the seg6_do_srh_encap() function extracts the original packet's
flow label and set it as the outer IPv6 flow label. There are two issues
with this behaviour:a) There is no guarantee that the inner flow label is set by the source.
b) If the original packet is not IPv6, the flow label will be set to
zero (e.g., IPv4 or L2 encap).This patch adds a function, named seg6_make_flowlabel(), that computes a
flow label from a given skb. It supports IPv6, IPv4 and L2 payloads, and
leverages the per namespace 'seg6_flowlabel" sysctl value.The currently support behaviours are as follows:
-1 set flowlabel to zero.
0 copy flowlabel from Inner paceket in case of Inner IPv6
(Set flowlabel to 0 in case IPv4/L2)
1 Compute the flowlabel using seg6_make_flowlabel()This patch has been tested for IPv6, IPv4, and L2 traffic.
Signed-off-by: Ahmed Abdelsalam
Acked-by: David Lebrun
Signed-off-by: David S. Miller
23 Apr, 2018
1 commit
-
In case of seg6 in encap mode, seg6_do_srh_encap() calls set_tun_src()
in order to set the src addr of outer IPv6 header.The net_device is required for set_tun_src(). However calling ip6_dst_idev()
on dst_entry in case of IPv4 traffic results on the following bug.Using just dst->dev should fix this BUG.
[ 196.242461] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[ 196.242975] PGD 800000010f076067 P4D 800000010f076067 PUD 10f060067 PMD 0
[ 196.243329] Oops: 0000 [#1] SMP PTI
[ 196.243468] Modules linked in: nfsd auth_rpcgss nfs_acl nfs lockd grace fscache sunrpc crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd input_leds glue_helper led_class pcspkr serio_raw mac_hid video autofs4 hid_generic usbhid hid e1000 i2c_piix4 ahci pata_acpi libahci
[ 196.244362] CPU: 2 PID: 1089 Comm: ping Not tainted 4.16.0+ #1
[ 196.244606] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 196.244968] RIP: 0010:seg6_do_srh_encap+0x1ac/0x300
[ 196.245236] RSP: 0018:ffffb2ce00b23a60 EFLAGS: 00010202
[ 196.245464] RAX: 0000000000000000 RBX: ffff8c7f53eea300 RCX: 0000000000000000
[ 196.245742] RDX: 0000f10000000000 RSI: ffff8c7f52085a6c RDI: ffff8c7f41166850
[ 196.246018] RBP: ffffb2ce00b23aa8 R08: 00000000000261e0 R09: ffff8c7f41166800
[ 196.246294] R10: ffffdce5040ac780 R11: ffff8c7f41166828 R12: ffff8c7f41166808
[ 196.246570] R13: ffff8c7f52085a44 R14: ffffffffb73211c0 R15: ffff8c7e69e44200
[ 196.246846] FS: 00007fc448789700(0000) GS:ffff8c7f59d00000(0000) knlGS:0000000000000000
[ 196.247286] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 196.247526] CR2: 0000000000000000 CR3: 000000010f05a000 CR4: 00000000000406e0
[ 196.247804] Call Trace:
[ 196.247972] seg6_do_srh+0x15b/0x1c0
[ 196.248156] seg6_output+0x3c/0x220
[ 196.248341] ? prandom_u32+0x14/0x20
[ 196.248526] ? ip_idents_reserve+0x6c/0x80
[ 196.248723] ? __ip_select_ident+0x90/0x100
[ 196.248923] ? ip_append_data.part.50+0x6c/0xd0
[ 196.249133] lwtunnel_output+0x44/0x70
[ 196.249328] ip_send_skb+0x15/0x40
[ 196.249515] raw_sendmsg+0x8c3/0xac0
[ 196.249701] ? _copy_from_user+0x2e/0x60
[ 196.249897] ? rw_copy_check_uvector+0x53/0x110
[ 196.250106] ? _copy_from_user+0x2e/0x60
[ 196.250299] ? copy_msghdr_from_user+0xce/0x140
[ 196.250508] sock_sendmsg+0x36/0x40
[ 196.250690] ___sys_sendmsg+0x292/0x2a0
[ 196.250881] ? _cond_resched+0x15/0x30
[ 196.251074] ? copy_termios+0x1e/0x70
[ 196.251261] ? _copy_to_user+0x22/0x30
[ 196.251575] ? tty_mode_ioctl+0x1c3/0x4e0
[ 196.251782] ? _cond_resched+0x15/0x30
[ 196.251972] ? mutex_lock+0xe/0x30
[ 196.252152] ? vvar_fault+0xd2/0x110
[ 196.252337] ? __do_fault+0x1f/0xc0
[ 196.252521] ? __handle_mm_fault+0xc1f/0x12d0
[ 196.252727] ? __sys_sendmsg+0x63/0xa0
[ 196.252919] __sys_sendmsg+0x63/0xa0
[ 196.253107] do_syscall_64+0x72/0x200
[ 196.253305] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 196.253530] RIP: 0033:0x7fc4480b0690
[ 196.253715] RSP: 002b:00007ffde9f252f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 196.254053] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007fc4480b0690
[ 196.254331] RDX: 0000000000000000 RSI: 000000000060a360 RDI: 0000000000000003
[ 196.254608] RBP: 00007ffde9f253f0 R08: 00000000002d1e81 R09: 0000000000000002
[ 196.254884] R10: 00007ffde9f250c0 R11: 0000000000000246 R12: 0000000000b22070
[ 196.255205] R13: 20c49ba5e353f7cf R14: 431bde82d7b634db R15: 00007ffde9f278fe
[ 196.255484] Code: a5 0f b6 45 c0 41 88 41 28 41 0f b6 41 2c 48 c1 e0 04 49 8b 54 01 38 49 8b 44 01 30 49 89 51 20 49 89 41 18 48 8b 83 b0 00 00 00 8b 30 49 8b 86 08 0b 00 00 48 8b 40 20 48 8b 50 08 48 0b 10
[ 196.256190] RIP: seg6_do_srh_encap+0x1ac/0x300 RSP: ffffb2ce00b23a60
[ 196.256445] CR2: 0000000000000000
[ 196.256676] ---[ end trace 71af7d093603885c ]---Fixes: 8936ef7604c11 ("ipv6: sr: fix NULL pointer dereference when setting encap source address")
Signed-off-by: Ahmed Abdelsalam
Acked-by: David Lebrun
Signed-off-by: David S. Miller
31 Mar, 2018
1 commit
-
Enabling TSO can lead to abysmal performances when using seg6 in
encap mode, such as with the ixgbe driver. This patch adds a call to
iptunnel_handle_offloads() to remove the encapsulation bit if needed.Before:
root@comp4-seg6bpf:~# iperf3 -c fc00::55
Connecting to host fc00::55, port 5201
[ 4] local fc45::4 port 36592 connected to fc00::55 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 196 KBytes 1.60 Mbits/sec 47 6.66 KBytes
[ 4] 1.00-2.00 sec 304 KBytes 2.49 Mbits/sec 100 5.33 KBytes
[ 4] 2.00-3.00 sec 284 KBytes 2.32 Mbits/sec 92 5.33 KBytesAfter:
root@comp4-seg6bpf:~# iperf3 -c fc00::55
Connecting to host fc00::55, port 5201
[ 4] local fc45::4 port 43062 connected to fc00::55 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 1.03 GBytes 8.89 Gbits/sec 0 743 KBytes
[ 4] 1.00-2.00 sec 1.03 GBytes 8.87 Gbits/sec 0 743 KBytes
[ 4] 2.00-3.00 sec 1.03 GBytes 8.87 Gbits/sec 0 743 KBytesReported-by: Tom Herbert
Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
23 Mar, 2018
2 commits
-
When using seg6 in encap mode, we call ipv6_dev_get_saddr() to set the
source address of the outer IPv6 header, in case none was specified.
Using skb->dev can lead to BUG() when it is in an inconsistent state.
This patch uses the net_device attached to the skb's dst instead.[940807.667429] BUG: unable to handle kernel NULL pointer dereference at 000000000000047c
[940807.762427] IP: ipv6_dev_get_saddr+0x8b/0x1d0
[940807.815725] PGD 0 P4D 0
[940807.847173] Oops: 0000 [#1] SMP PTI
[940807.890073] Modules linked in:
[940807.927765] CPU: 6 PID: 0 Comm: swapper/6 Tainted: G W 4.16.0-rc1-seg6bpf+ #2
[940808.028988] Hardware name: HP ProLiant DL120 G6/ProLiant DL120 G6, BIOS O26 09/06/2010
[940808.128128] RIP: 0010:ipv6_dev_get_saddr+0x8b/0x1d0
[940808.187667] RSP: 0018:ffff88043fd836b0 EFLAGS: 00010206
[940808.251366] RAX: 0000000000000005 RBX: ffff88042cb1c860 RCX: 00000000000000fe
[940808.338025] RDX: 00000000000002c0 RSI: ffff88042cb1c860 RDI: 0000000000004500
[940808.424683] RBP: ffff88043fd83740 R08: 0000000000000000 R09: ffffffffffffffff
[940808.511342] R10: 0000000000000040 R11: 0000000000000000 R12: ffff88042cb1c850
[940808.598012] R13: ffffffff8208e380 R14: ffff88042ac8da00 R15: 0000000000000002
[940808.684675] FS: 0000000000000000(0000) GS:ffff88043fd80000(0000) knlGS:0000000000000000
[940808.783036] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[940808.852975] CR2: 000000000000047c CR3: 00000004255fe000 CR4: 00000000000006e0
[940808.939634] Call Trace:
[940808.970041]
[940808.995250] ? ip6t_do_table+0x265/0x640
[940809.043341] seg6_do_srh_encap+0x28f/0x300
[940809.093516] ? seg6_do_srh+0x1a0/0x210
[940809.139528] seg6_do_srh+0x1a0/0x210
[940809.183462] seg6_output+0x28/0x1e0
[940809.226358] lwtunnel_output+0x3f/0x70
[940809.272370] ip6_xmit+0x2b8/0x530
[940809.313185] ? ac6_proc_exit+0x20/0x20
[940809.359197] inet6_csk_xmit+0x7d/0xc0
[940809.404173] tcp_transmit_skb+0x548/0x9a0
[940809.453304] __tcp_retransmit_skb+0x1a8/0x7a0
[940809.506603] ? ip6_default_advmss+0x40/0x40
[940809.557824] ? tcp_current_mss+0x24/0x90
[940809.605925] tcp_retransmit_skb+0xd/0x80
[940809.654016] tcp_xmit_retransmit_queue.part.17+0xf9/0x210
[940809.719797] tcp_ack+0xa47/0x1110
[940809.760612] tcp_rcv_established+0x13c/0x570
[940809.812865] tcp_v6_do_rcv+0x151/0x3d0
[940809.858879] tcp_v6_rcv+0xa5c/0xb10
[940809.901770] ? seg6_output+0xdd/0x1e0
[940809.946745] ip6_input_finish+0xbb/0x460
[940809.994837] ip6_input+0x74/0x80
[940810.034612] ? ip6_rcv_finish+0xb0/0xb0
[940810.081663] ipv6_rcv+0x31c/0x4c0
...Fixes: 6c8702c60b886 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Reported-by: Tom Herbert
Signed-off-by: David Lebrun
Signed-off-by: David S. Miller -
The seg6_build_state() function is called with RCU read lock held,
so we cannot use GFP_KERNEL. This patch uses GFP_ATOMIC instead.[ 92.770271] =============================
[ 92.770628] WARNING: suspicious RCU usage
[ 92.770921] 4.16.0-rc4+ #12 Not tainted
[ 92.771277] -----------------------------
[ 92.771585] ./include/linux/rcupdate.h:302 Illegal context switch in RCU read-side critical section!
[ 92.772279]
[ 92.772279] other info that might help us debug this:
[ 92.772279]
[ 92.773067]
[ 92.773067] rcu_scheduler_active = 2, debug_locks = 1
[ 92.773514] 2 locks held by ip/2413:
[ 92.773765] #0: (rtnl_mutex){+.+.}, at: [] rtnetlink_rcv_msg+0x441/0x4d0
[ 92.774377] #1: (rcu_read_lock){....}, at: [] lwtunnel_build_state+0x59/0x210
[ 92.775065]
[ 92.775065] stack backtrace:
[ 92.775371] CPU: 0 PID: 2413 Comm: ip Not tainted 4.16.0-rc4+ #12
[ 92.775791] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014
[ 92.776608] Call Trace:
[ 92.776852] dump_stack+0x7d/0xbc
[ 92.777130] __schedule+0x133/0xf00
[ 92.777393] ? unwind_get_return_address_ptr+0x50/0x50
[ 92.777783] ? __sched_text_start+0x8/0x8
[ 92.778073] ? rcu_is_watching+0x19/0x30
[ 92.778383] ? kernel_text_address+0x49/0x60
[ 92.778800] ? __kernel_text_address+0x9/0x30
[ 92.779241] ? unwind_get_return_address+0x29/0x40
[ 92.779727] ? pcpu_alloc+0x102/0x8f0
[ 92.780101] _cond_resched+0x23/0x50
[ 92.780459] __mutex_lock+0xbd/0xad0
[ 92.780818] ? pcpu_alloc+0x102/0x8f0
[ 92.781194] ? seg6_build_state+0x11d/0x240
[ 92.781611] ? save_stack+0x9b/0xb0
[ 92.781965] ? __ww_mutex_wakeup_for_backoff+0xf0/0xf0
[ 92.782480] ? seg6_build_state+0x11d/0x240
[ 92.782925] ? lwtunnel_build_state+0x1bd/0x210
[ 92.783393] ? ip6_route_info_create+0x687/0x1640
[ 92.783846] ? ip6_route_add+0x74/0x110
[ 92.784236] ? inet6_rtm_newroute+0x8a/0xd0Fixes: 6c8702c60b886 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
26 Aug, 2017
2 commits
-
This patch implements the L2 frame encapsulation mechanism, referred to
as T.Encaps.L2 in the SRv6 specifications [1].A new type of SRv6 tunnel mode is added (SEG6_IPTUN_MODE_L2ENCAP). It only
accepts packets with an existing MAC header (i.e., it will not work for
locally generated packets). The resulting packet looks like IPv6 -> SRH ->
Ethernet -> original L3 payload. The next header field of the SRH is set to
NEXTHDR_NONE.[1] https://tools.ietf.org/html/draft-filsfils-spring-srv6-network-programming-01
Signed-off-by: David Lebrun
Signed-off-by: David S. Miller -
This patch enables the SRv6 encapsulation mode to carry an IPv4 payload.
All the infrastructure was already present, I just had to add a parameter
to seg6_do_srh_encap() to specify the inner packet protocol, and perform
some additional checks.Usage example:
ip route add 1.2.3.4 encap seg6 mode encap segs fc00::1,fc00::2 dev eth0Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
08 Aug, 2017
1 commit
-
This patch exports the seg6_do_srh_encap() and seg6_do_srh_inline()
functions. It also removes the CONFIG_IPV6_SEG6_INLINE knob
that enabled the compilation of seg6_do_srh_inline(). This function
is now built-in.Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
30 May, 2017
1 commit
-
Pass extack arg down to lwtunnel_build_state and the build_state callbacks.
Add messages for failures in lwtunnel_build_state, and add the extarg to
nla_parse where possible in the build_state callbacks.Signed-off-by: David Ahern
Signed-off-by: David S. Miller
18 Apr, 2017
1 commit
-
When a locally generated packet receives an SRH with two or more segments,
the remaining headroom is too small to push an ethernet header. This patch
ensures that the headroom is large enough after SRH push.The BUG generated the following trace.
[ 192.950285] skbuff: skb_under_panic: text:ffffffff81809675 len:198 put:14 head:ffff88006f306400 data:ffff88006f3063fa tail:0xc0 end:0x2c0 dev:A-1
[ 192.952456] ------------[ cut here ]------------
[ 192.953218] kernel BUG at net/core/skbuff.c:105!
[ 192.953411] invalid opcode: 0000 [#1] PREEMPT SMP
[ 192.953411] Modules linked in:
[ 192.953411] CPU: 5 PID: 3433 Comm: ping6 Not tainted 4.11.0-rc3+ #237
[ 192.953411] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
[ 192.953411] task: ffff88007c2d42c0 task.stack: ffffc90000ef4000
[ 192.953411] RIP: 0010:skb_panic+0x61/0x70
[ 192.953411] RSP: 0018:ffffc90000ef7900 EFLAGS: 00010286
[ 192.953411] RAX: 0000000000000085 RBX: 00000000000086dd RCX: 0000000000000201
[ 192.953411] RDX: 0000000080000201 RSI: ffffffff81d104c5 RDI: 00000000ffffffff
[ 192.953411] RBP: ffffc90000ef7920 R08: 0000000000000001 R09: 0000000000000000
[ 192.953411] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 192.953411] R13: ffff88007c5a4000 R14: ffff88007b363d80 R15: 00000000000000b8
[ 192.953411] FS: 00007f94b558b700(0000) GS:ffff88007fd40000(0000) knlGS:0000000000000000
[ 192.953411] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 192.953411] CR2: 00007fff5ecd5080 CR3: 0000000074141000 CR4: 00000000001406e0
[ 192.953411] Call Trace:
[ 192.953411] skb_push+0x3b/0x40
[ 192.953411] eth_header+0x25/0xc0
[ 192.953411] neigh_resolve_output+0x168/0x230
[ 192.953411] ? ip6_finish_output2+0x242/0x8f0
[ 192.953411] ip6_finish_output2+0x242/0x8f0
[ 192.953411] ? ip6_finish_output2+0x76/0x8f0
[ 192.953411] ip6_finish_output+0xa8/0x1d0
[ 192.953411] ip6_output+0x64/0x2d0
[ 192.953411] ? ip6_output+0x73/0x2d0
[ 192.953411] ? ip6_dst_check+0xb5/0xc0
[ 192.953411] ? dst_cache_per_cpu_get.isra.2+0x40/0x80
[ 192.953411] seg6_output+0xb0/0x220
[ 192.953411] lwtunnel_output+0xcf/0x210
[ 192.953411] ? lwtunnel_output+0x59/0x210
[ 192.953411] ip6_local_out+0x38/0x70
[ 192.953411] ip6_send_skb+0x2a/0xb0
[ 192.953411] ip6_push_pending_frames+0x48/0x50
[ 192.953411] rawv6_sendmsg+0xa39/0xf10
[ 192.953411] ? __lock_acquire+0x489/0x890
[ 192.953411] ? __mutex_lock+0x1fc/0x970
[ 192.953411] ? __lock_acquire+0x489/0x890
[ 192.953411] ? __mutex_lock+0x1fc/0x970
[ 192.953411] ? tty_ioctl+0x283/0xec0
[ 192.953411] inet_sendmsg+0x45/0x1d0
[ 192.953411] ? _copy_from_user+0x54/0x80
[ 192.953411] sock_sendmsg+0x33/0x40
[ 192.953411] SYSC_sendto+0xef/0x170
[ 192.953411] ? entry_SYSCALL_64_fastpath+0x5/0xc2
[ 192.953411] ? trace_hardirqs_on_caller+0x12b/0x1b0
[ 192.953411] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 192.953411] SyS_sendto+0x9/0x10
[ 192.953411] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 192.953411] RIP: 0033:0x7f94b453db33
[ 192.953411] RSP: 002b:00007fff5ecd0578 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 192.953411] RAX: ffffffffffffffda RBX: 00007fff5ecd16e0 RCX: 00007f94b453db33
[ 192.953411] RDX: 0000000000000040 RSI: 000055a78352e9c0 RDI: 0000000000000003
[ 192.953411] RBP: 00007fff5ecd1690 R08: 000055a78352c940 R09: 000000000000001c
[ 192.953411] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a783321e10
[ 192.953411] R13: 000055a7839890c0 R14: 0000000000000004 R15: 0000000000000000
[ 192.953411] Code: 00 00 48 89 44 24 10 8b 87 c4 00 00 00 48 89 44 24 08 48 8b 87 d8 00 00 00 48 c7 c7 90 58 d2 81 48 89 04 24 31 c0 e8 4f 70 9a ff 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 48 8b 97 d8 00 00
[ 192.953411] RIP: skb_panic+0x61/0x70 RSP: ffffc90000ef7900
[ 193.000186] ---[ end trace bd0b89fabdf2f92c ]---
[ 193.000951] Kernel panic - not syncing: Fatal exception in interrupt
[ 193.001137] Kernel Offset: disabled
[ 193.001169] ---[ end Kernel panic - not syncing: Fatal exception in interruptFixes: 19d5a26f5ef8de5dcb78799feaf404d717b1aac3 ("ipv6: sr: expand skb head only if necessary")
Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
14 Apr, 2017
1 commit
-
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)Signed-off-by: Johannes Berg
Signed-off-by: David S. Miller
28 Mar, 2017
1 commit
-
When CONFIG_IPV6_SEG6_LWTUNNEL is selected, automatically select DST_CACHE.
This allows to remove multiple ifdefs.Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
25 Mar, 2017
2 commits
-
We already use dst_cache in seg6_output, when handling locally generated
packets. We extend it in seg6_input, to also handle forwarded packets, and avoid
unnecessary fib lookups.Performances for SRH encapsulation before the patch:
Result: OK: 5656067(c5655678+d388) usec, 5000000 (1000byte,0frags)
884006pps 7072Mb/sec (7072048000bps) errors: 0Performances after the patch:
Result: OK: 4774543(c4774084+d459) usec, 5000000 (1000byte,0frags)
1047220pps 8377Mb/sec (8377760000bps) errors: 0Signed-off-by: David Lebrun
Signed-off-by: David S. Miller -
To insert or encapsulate a packet with an SRH, we need a large enough skb
headroom. Currently, we are using pskb_expand_head to inconditionally increase
the size of the headroom by the amount needed by the SRH (and IPv6 header).
If this reallocation is performed by another CPU than the one that initially
allocated the skb, then when the initial CPU kfree the skb, it will enter the
__slab_free slowpath, impacting performances.This patch replaces pskb_expand_head with skb_cow_head, that will reallocate the
skb head only if the headroom is not large enough.Performances for SRH encapsulation before the patch:
Result: OK: 7348320(c7347271+d1048) usec, 5000000 (1000byte,0frags)
680427pps 5443Mb/sec (5443416000bps) errors: 0Performances after the patch:
Result: OK: 5656067(c5655678+d388) usec, 5000000 (1000byte,0frags)
884006pps 7072Mb/sec (7072048000bps) errors: 0Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
08 Feb, 2017
1 commit
-
Fixes the following sparse warnings:
net/ipv6/seg6_iptunnel.c:58:5: warning:
symbol 'nla_put_srh' was not declared. Should it be static?
net/ipv6/seg6_iptunnel.c:238:5: warning:
symbol 'seg6_input' was not declared. Should it be static?
net/ipv6/seg6_iptunnel.c:254:5: warning:
symbol 'seg6_output' was not declared. Should it be static?Signed-off-by: Wei Yongjun
Signed-off-by: David S. Miller
31 Jan, 2017
1 commit
-
Nothing about lwt state requires a device reference, so remove the
input argument.Signed-off-by: David Ahern
Signed-off-by: David S. Miller
25 Jan, 2017
1 commit
-
Modules implementing lwtunnel ops should not be allowed to unload
while there is state alive using those ops, so specify the owning
module for all lwtunnel ops.Signed-off-by: Robert Shearman
Signed-off-by: David S. Miller
14 Jan, 2017
1 commit
-
When CONFIG_PREEMPT=y, CONFIG_IPV6=m and CONFIG_SEG6_HMAC=y,
seg6_hmac_init() is called during the initialization of the ipv6 module.
This causes a subsequent call to smp_processor_id() with preemption
enabled, resulting in the following trace.[ 20.451460] BUG: using smp_processor_id() in preemptible [00000000] code: systemd/1
[ 20.452556] caller is debug_smp_processor_id+0x17/0x19
[ 20.453304] CPU: 0 PID: 1 Comm: systemd Not tainted 4.9.0-rc5-00973-g46738b1 #1
[ 20.454406] ffffc9000062fc18 ffffffff813607b2 0000000000000000 ffffffff81a7f782
[ 20.455528] ffffc9000062fc48 ffffffff813778dc 0000000000000000 00000000001dcf98
[ 20.456539] ffffffffa003bd08 ffffffff81af93e0 ffffc9000062fc58 ffffffff81377905
[ 20.456539] Call Trace:
[ 20.456539] [] dump_stack+0x63/0x7f
[ 20.456539] [] check_preemption_disabled+0xd1/0xe3
[ 20.456539] [] debug_smp_processor_id+0x17/0x19
[ 20.460260] [] seg6_hmac_init+0xfa/0x192 [ipv6]
[ 20.460260] [] seg6_init+0x39/0x6f [ipv6]
[ 20.460260] [] inet6_init+0x21a/0x321 [ipv6]
[ 20.460260] [] ? 0xffffffffa0061000
[ 20.460260] [] do_one_initcall+0x8b/0x115
[ 20.460260] [] do_init_module+0x53/0x1c4
[ 20.460260] [] load_module+0x1153/0x14ec
[ 20.460260] [] SYSC_finit_module+0x8c/0xb9
[ 20.460260] [] ? SYSC_finit_module+0x8c/0xb9
[ 20.460260] [] SyS_finit_module+0x9/0xb
[ 20.460260] [] do_syscall_64+0x62/0x75
[ 20.460260] [] entry_SYSCALL64_slow_path+0x25/0x25Moreover, dst_cache_* functions also call smp_processor_id(), generating
a similar trace.This patch uses raw_cpu_ptr() in seg6_hmac_init() rather than this_cpu_ptr()
and disable preemption when using dst_cache_* functions.Signed-off-by: David Lebrun
Signed-off-by: David S. Miller
10 Nov, 2016
2 commits
-
This patch enables the verification of the HMAC signature for transiting
SR-enabled packets, and its insertion on encapsulated/injected SRH.Signed-off-by: David Lebrun
Signed-off-by: David S. Miller -
This patch creates a new type of interfaceless lightweight tunnel (SEG6),
enabling the encapsulation and injection of SRH within locally emitted
packets and forwarded packets.>From a configuration viewpoint, a seg6 tunnel would be configured as follows:
ip -6 ro ad fc00::1/128 encap seg6 mode encap segs fc42::1,fc42::2,fc42::3 dev eth0
Any packet whose destination address is fc00::1 would thus be encapsulated
within an outer IPv6 header containing the SRH with three segments, and would
actually be routed to the first segment of the list. If `mode inline' was
specified instead of `mode encap', then the SRH would be directly inserted
after the IPv6 header without outer encapsulation.The inline mode is only available if CONFIG_IPV6_SEG6_INLINE is enabled. This
feature was made configurable because direct header insertion may break
several mechanisms such as PMTUD or IPSec AH.Signed-off-by: David Lebrun
Signed-off-by: David S. Miller