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ip: IPv4 Fragmentation fix for l2fragmetable size

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Type: fix

The l2unfragmentable size is not included in the calculation of 'max', the maximum amount of data that can be added to a fragment, therefore the fragments created are too big.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Id1e949ad98203b6f8ea2f55322ef6fa3d507e2a6
This commit is contained in:
Neale Ranns 2022-03-08 13:24:28 +00:00 committed by Ole Tr�an
parent 23e5f0923b
commit 346c24723b
2 changed files with 9 additions and 11 deletions
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17
src/vnet/ip/ip_frag.c
View File

@ -95,7 +95,7 @@ ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu,
{
vlib_buffer_t *from_b;
ip4_header_t *ip4;
u16 len, max, rem, ip_frag_id, ip_frag_offset;
u16 len, max, rem, ip_frag_id, ip_frag_offset, head_bytes;
u8 *org_from_packet, more;
from_b = vlib_get_buffer (vm, from_bi);
@ -103,9 +103,9 @@ ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu,
ip4 = vlib_buffer_get_current (from_b) + l2unfragmentablesize;
rem = clib_net_to_host_u16 (ip4->length) - sizeof (ip4_header_t);
max =
(clib_min (mtu, vlib_buffer_get_default_data_size (vm)) -
sizeof (ip4_header_t)) & ~0x7;
head_bytes = sizeof (ip4_header_t) + l2unfragmentablesize;
max = (clib_min (mtu, vlib_buffer_get_default_data_size (vm)) - head_bytes) &
~0x7;
if (rem >
(vlib_buffer_length_in_chain (vm, from_b) - sizeof (ip4_header_t)))
@ -142,8 +142,7 @@ ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu,
u8 *from_data = (void *) (ip4 + 1);
vlib_buffer_t *org_from_b = from_b;
u16 fo = 0;
u16 left_in_from_buffer =
from_b->current_length - (l2unfragmentablesize + sizeof (ip4_header_t));
u16 left_in_from_buffer = from_b->current_length - head_bytes;
u16 ptr = 0;
/* Do the actual fragmentation */
@ -166,8 +165,7 @@ ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu,
/* Copy ip4 header */
to_data = vlib_buffer_get_current (to_b);
clib_memcpy_fast (to_data, org_from_packet,
l2unfragmentablesize + sizeof (ip4_header_t));
clib_memcpy_fast (to_data, org_from_packet, head_bytes);
to_ip4 = (ip4_header_t *) (to_data + l2unfragmentablesize);
to_data = (void *) (to_ip4 + 1);
vnet_buffer (to_b)->l3_hdr_offset = to_b->current_data;
@ -213,8 +211,7 @@ ip4_frag_do_fragment (vlib_main_t * vm, u32 from_bi, u16 mtu,
}
to_b->flags |= VNET_BUFFER_F_IS_IP4;
to_b->current_length =
len + sizeof (ip4_header_t) + l2unfragmentablesize;
to_b->current_length = len + head_bytes;
to_ip4->fragment_id = ip_frag_id;
to_ip4->flags_and_fragment_offset =

3
test/test_map.py
View File

@ -388,7 +388,8 @@ class TestMAP(VppTestCase):
self.pg_send(self.pg0, v4*1)
rx = self.pg1.get_capture(2)
frags = fragment_rfc791(v4[1], 1000)
# 1000-sizeof(ip6_header_t) = 960.
frags = fragment_rfc791(v4[1], 960)
frags[0].id = 0
frags[1].id = 0
frags[0].ttl -= 1