1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
/*
* Copyright (c) 2021 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef included_pnat_node_h
#define included_pnat_node_h
#include "pnat.h"
#include <pnat/pnat.api_enum.h>
#include <vnet/feature/feature.h>
#include <vnet/udp/udp_packet.h>
#include <vnet/ip/format.h>
/* PNAT next-nodes */
typedef enum { PNAT_NEXT_DROP, PNAT_N_NEXT } pnat_next_t;
// u8 *format_pnat_key(u8 *s, va_list *args);
u8 *format_pnat_5tuple(u8 *s, va_list *args);
static inline u8 *format_pnat_trace(u8 *s, va_list *args) {
CLIB_UNUSED(vlib_main_t * vm) = va_arg(*args, vlib_main_t *);
CLIB_UNUSED(vlib_node_t * node) = va_arg(*args, vlib_node_t *);
pnat_trace_t *t = va_arg(*args, pnat_trace_t *);
s = format(s, "pnat: index %d\n", t->pool_index);
if (t->pool_index != ~0) {
s = format(s, " match: %U\n", format_pnat_5tuple, &t->match);
s = format(s, " rewrite: %U", format_pnat_5tuple, &t->rewrite);
}
return s;
}
/*
* Given a packet and rewrite instructions from a translation modify packet.
*/
static u32 pnat_rewrite_ip4(u32 pool_index, ip4_header_t *ip) {
pnat_main_t *pm = &pnat_main;
if (pool_is_free_index(pm->translations, pool_index))
return PNAT_ERROR_REWRITE;
pnat_translation_t *t = pool_elt_at_index(pm->translations, pool_index);
ip_csum_t csumd = 0;
if (t->instructions & PNAT_INSTR_DESTINATION_ADDRESS) {
csumd = ip_csum_sub_even(csumd, ip->dst_address.as_u32);
csumd = ip_csum_add_even(csumd, t->post_da.as_u32);
ip->dst_address = t->post_da;
}
if (t->instructions & PNAT_INSTR_SOURCE_ADDRESS) {
csumd = ip_csum_sub_even(csumd, ip->src_address.as_u32);
csumd = ip_csum_add_even(csumd, t->post_sa.as_u32);
ip->src_address = t->post_sa;
}
ip_csum_t csum = ip->checksum;
csum = ip_csum_sub_even(csum, csumd);
ip->checksum = ip_csum_fold(csum);
ASSERT(ip->checksum == ip4_header_checksum(ip));
/* L4 ports */
if (ip->protocol == IP_PROTOCOL_TCP) {
tcp_header_t *tcp = ip4_next_header(ip);
ip_csum_t l4csum = tcp->checksum;
if (t->instructions & PNAT_INSTR_DESTINATION_PORT) {
l4csum = ip_csum_sub_even(l4csum, tcp->dst_port);
l4csum = ip_csum_add_even(l4csum, clib_net_to_host_u16(t->post_dp));
tcp->dst_port = clib_net_to_host_u16(t->post_dp);
}
if (t->instructions & PNAT_INSTR_SOURCE_PORT) {
l4csum = ip_csum_sub_even(l4csum, tcp->src_port);
l4csum = ip_csum_add_even(l4csum, clib_net_to_host_u16(t->post_sp));
tcp->src_port = clib_net_to_host_u16(t->post_sp);
}
l4csum = ip_csum_sub_even(l4csum, csumd);
tcp->checksum = ip_csum_fold(l4csum);
} else if (ip->protocol == IP_PROTOCOL_UDP) {
udp_header_t *udp = ip4_next_header(ip);
ip_csum_t l4csum = udp->checksum;
if (t->instructions & PNAT_INSTR_DESTINATION_PORT) {
l4csum = ip_csum_sub_even(l4csum, udp->dst_port);
l4csum = ip_csum_add_even(l4csum, clib_net_to_host_u16(t->post_dp));
udp->dst_port = clib_net_to_host_u16(t->post_dp);
}
if (t->instructions & PNAT_INSTR_SOURCE_PORT) {
l4csum = ip_csum_sub_even(l4csum, udp->src_port);
l4csum = ip_csum_add_even(l4csum, clib_net_to_host_u16(t->post_sp));
udp->src_port = clib_net_to_host_u16(t->post_sp);
}
if (udp->checksum) {
l4csum = ip_csum_sub_even(l4csum, csumd);
udp->checksum = ip_csum_fold(l4csum);
}
}
return PNAT_ERROR_NONE;
}
/*
* Lookup the packet tuple in the flow cache, given the lookup mask.
* If a binding is found, rewrite the packet according to instructions,
* otherwise follow configured default action (forward, punt or drop)
*/
static_always_inline uword pnat_node_inline(vlib_main_t *vm,
vlib_node_runtime_t *node,
vlib_frame_t *frame,
pnat_attachment_point_t attachment,
int dir) {
pnat_main_t *pm = &pnat_main;
u32 n_left_from, *from;
u16 nexts[VLIB_FRAME_SIZE] = {0}, *next = nexts;
u32 pool_indicies[VLIB_FRAME_SIZE], *pi = pool_indicies;
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
clib_bihash_kv_16_8_t kv, value;
ip4_header_t *ip0;
from = vlib_frame_vector_args(frame);
n_left_from = frame->n_vectors;
vlib_get_buffers(vm, from, b, n_left_from);
pnat_interface_t *interface;
/* Stage 1: build vector of flow hash (based on lookup mask) */
while (n_left_from > 0) {
u32 sw_if_index0 = vnet_buffer(b[0])->sw_if_index[dir];
u16 sport0 = vnet_buffer(b[0])->ip.reass.l4_src_port;
u16 dport0 = vnet_buffer(b[0])->ip.reass.l4_dst_port;
u32 iph_offset =
dir == VLIB_TX ? vnet_buffer(b[0])->ip.save_rewrite_length : 0;
ip0 = (ip4_header_t *)(vlib_buffer_get_current(b[0]) + iph_offset);
interface = pnat_interface_by_sw_if_index(sw_if_index0);
ASSERT(interface);
pnat_mask_fast_t mask = interface->lookup_mask_fast[attachment];
pnat_calc_key(sw_if_index0, attachment, ip0->src_address,
ip0->dst_address, ip0->protocol, sport0, dport0, mask,
&kv);
/* By default pass packet to next node in the feature chain */
vnet_feature_next_u16(next, b[0]);
if (clib_bihash_search_16_8(&pm->flowhash, &kv, &value) == 0) {
/* Cache hit */
*pi = value.value;
u32 errno0 = pnat_rewrite_ip4(value.value, ip0);
if (PREDICT_FALSE(errno0)) {
next[0] = PNAT_NEXT_DROP;
b[0]->error = node->errors[errno0];
}
} else {
/* Cache miss */
*pi = ~0;
}
next += 1;
/*next: */
n_left_from -= 1;
b += 1;
pi += 1;
}
/* Packet trace */
if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE))) {
u32 i;
b = bufs;
pi = pool_indicies;
for (i = 0; i < frame->n_vectors; i++) {
if (b[0]->flags & VLIB_BUFFER_IS_TRACED) {
pnat_trace_t *t = vlib_add_trace(vm, node, b[0], sizeof(*t));
if (*pi != ~0) {
if (!pool_is_free_index(pm->translations, *pi)) {
pnat_translation_t *tr =
pool_elt_at_index(pm->translations, *pi);
t->match = tr->match;
t->rewrite = tr->rewrite;
}
}
t->pool_index = *pi;
b += 1;
pi += 1;
} else
break;
}
}
vlib_buffer_enqueue_to_next(vm, node, from, nexts, frame->n_vectors);
return frame->n_vectors;
}
#endif
|
