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Vector Packet Processing
nat_inlines.h
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1 /*
2  * Copyright (c) 2020 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef __included_lib_nat_inlines_h__
17 #define __included_lib_nat_inlines_h__
18 
19 #include <vnet/tcp/tcp_packet.h>
20 #include <vnet/ip/ip4_packet.h>
21 
22 static inline void
24 {
25  u32 v;
26 
27  v = clib_net_to_host_u32 (a->as_u32) + 1;
28  a->as_u32 = clib_host_to_net_u32 (v);
29 }
30 
31 always_inline void
33 {
34  u8 *data;
35  u8 opt_len, opts_len, kind;
36  u16 mss;
37 
38  if (!(mss_clamping && tcp_syn (tcp)))
39  return;
40 
41  opts_len = (tcp_doff (tcp) << 2) - sizeof (tcp_header_t);
42  data = (u8 *) (tcp + 1);
43  for (; opts_len > 0; opts_len -= opt_len, data += opt_len)
44  {
45  kind = data[0];
46 
47  if (kind == TCP_OPTION_EOL)
48  break;
49  else if (kind == TCP_OPTION_NOOP)
50  {
51  opt_len = 1;
52  continue;
53  }
54  else
55  {
56  if (opts_len < 2)
57  return;
58  opt_len = data[1];
59 
60  if (opt_len < 2 || opt_len > opts_len)
61  return;
62  }
63 
64  if (kind == TCP_OPTION_MSS)
65  {
66  mss = *(u16 *) (data + 2);
67  if (clib_net_to_host_u16 (mss) > mss_clamping)
68  {
69  u16 mss_value_net = clib_host_to_net_u16 (mss_clamping);
70  *sum =
71  ip_csum_update (*sum, mss, mss_value_net, ip4_header_t,
72  length);
73  clib_memcpy_fast (data + 2, &mss_value_net, 2);
74  }
75  return;
76  }
77  }
78 }
79 
81 nat_random_port (u32 *random_seed, u16 min, u16 max)
82 {
83  u32 rwide;
84  u16 r;
85 
86  rwide = random_u32 (random_seed);
87  r = rwide & 0xFFFF;
88  if (r >= min && r <= max)
89  return r;
90 
91  return min + (rwide % (max - min + 1));
92 }
93 
94 #endif /* __included_lib_nat_inlines_h__ */
95 
96 /*
97  * fd.io coding-style-patch-verification: ON
98  *
99  * Local Variables:
100  * eval: (c-set-style "gnu")
101  * End:
102  */
tcp_doff
#define tcp_doff(_th)
Definition: tcp_packet.h:78
TCP_OPTION_EOL
@ TCP_OPTION_EOL
End of options.
Definition: tcp_packet.h:104
tcp_packet.h
tcp_header_t
struct _tcp_header tcp_header_t
u16
unsigned short u16
Definition: types.h:57
TCP_OPTION_NOOP
@ TCP_OPTION_NOOP
No operation.
Definition: tcp_packet.h:105
r
vnet_hw_if_output_node_runtime_t * r
Definition: interface_output.c:1089
clib_memcpy_fast
static_always_inline void * clib_memcpy_fast(void *restrict dst, const void *restrict src, size_t n)
Definition: string.h:92
ip4_header_t
Definition: ip4_packet.h:87
tcp_syn
#define tcp_syn(_th)
Definition: tcp_packet.h:80
random_u32
static u32 random_u32(u32 *seed)
32-bit random number generator
Definition: random.h:69
static_always_inline
#define static_always_inline
Definition: clib.h:112
ip4_address_t
Definition: ip4_packet.h:50
increment_v4_address
static void increment_v4_address(ip4_address_t *a)
Definition: nat_inlines.h:23
data
u8 data[128]
Definition: ipsec_types.api:95
ip4_packet.h
always_inline
#define always_inline
Definition: rdma_mlx5dv.h:23
mss_clamping
static void mss_clamping(u16 mss_clamping, tcp_header_t *tcp, ip_csum_t *sum)
Definition: nat_inlines.h:32
u32
unsigned int u32
Definition: types.h:88
TCP_OPTION_MSS
@ TCP_OPTION_MSS
Limit MSS.
Definition: tcp_packet.h:106
length
char const int length
Definition: cJSON.h:163
ip_csum_update
#define ip_csum_update(sum, old, new, type, field)
Definition: ip_packet.h:295
u8
unsigned char u8
Definition: types.h:56
a
a
Definition: bitmap.h:525
ip_csum_t
uword ip_csum_t
Definition: ip_packet.h:245
nat_random_port
static_always_inline u16 nat_random_port(u32 *random_seed, u16 min, u16 max)
Definition: nat_inlines.h:81