libnftnl 1.2.7
byteorder.c
1/*
2 * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published
6 * by the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
10 */
11
12#include "internal.h"
13
14#include <stdio.h>
15#include <stdint.h>
16#include <string.h> /* for memcpy */
17#include <arpa/inet.h>
18#include <errno.h>
19#include <libmnl/libmnl.h>
20#include <linux/netfilter/nf_tables.h>
21#include <libnftnl/expr.h>
22#include <libnftnl/rule.h>
23
25 enum nft_registers sreg;
26 enum nft_registers dreg;
27 enum nft_byteorder_ops op;
28 unsigned int len;
29 unsigned int size;
30};
31
32static int
33nftnl_expr_byteorder_set(struct nftnl_expr *e, uint16_t type,
34 const void *data, uint32_t data_len)
35{
36 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
37
38 switch(type) {
39 case NFTNL_EXPR_BYTEORDER_SREG:
40 memcpy(&byteorder->sreg, data, data_len);
41 break;
42 case NFTNL_EXPR_BYTEORDER_DREG:
43 memcpy(&byteorder->dreg, data, data_len);
44 break;
45 case NFTNL_EXPR_BYTEORDER_OP:
46 memcpy(&byteorder->op, data, data_len);
47 break;
48 case NFTNL_EXPR_BYTEORDER_LEN:
49 memcpy(&byteorder->len, data, data_len);
50 break;
51 case NFTNL_EXPR_BYTEORDER_SIZE:
52 memcpy(&byteorder->size, data, data_len);
53 break;
54 }
55 return 0;
56}
57
58static const void *
59nftnl_expr_byteorder_get(const struct nftnl_expr *e, uint16_t type,
60 uint32_t *data_len)
61{
62 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
63
64 switch(type) {
65 case NFTNL_EXPR_BYTEORDER_SREG:
66 *data_len = sizeof(byteorder->sreg);
67 return &byteorder->sreg;
68 case NFTNL_EXPR_BYTEORDER_DREG:
69 *data_len = sizeof(byteorder->dreg);
70 return &byteorder->dreg;
71 case NFTNL_EXPR_BYTEORDER_OP:
72 *data_len = sizeof(byteorder->op);
73 return &byteorder->op;
74 case NFTNL_EXPR_BYTEORDER_LEN:
75 *data_len = sizeof(byteorder->len);
76 return &byteorder->len;
77 case NFTNL_EXPR_BYTEORDER_SIZE:
78 *data_len = sizeof(byteorder->size);
79 return &byteorder->size;
80 }
81 return NULL;
82}
83
84static int nftnl_expr_byteorder_cb(const struct nlattr *attr, void *data)
85{
86 const struct nlattr **tb = data;
87 int type = mnl_attr_get_type(attr);
88
89 if (mnl_attr_type_valid(attr, NFTA_BYTEORDER_MAX) < 0)
90 return MNL_CB_OK;
91
92 switch(type) {
93 case NFTA_BYTEORDER_SREG:
94 case NFTA_BYTEORDER_DREG:
95 case NFTA_BYTEORDER_OP:
96 case NFTA_BYTEORDER_LEN:
97 case NFTA_BYTEORDER_SIZE:
98 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
99 abi_breakage();
100 break;
101 }
102
103 tb[type] = attr;
104 return MNL_CB_OK;
105}
106
107static void
108nftnl_expr_byteorder_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
109{
110 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
111
112 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SREG)) {
113 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SREG,
114 htonl(byteorder->sreg));
115 }
116 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_DREG)) {
117 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_DREG,
118 htonl(byteorder->dreg));
119 }
120 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_OP)) {
121 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_OP,
122 htonl(byteorder->op));
123 }
124 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_LEN)) {
125 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_LEN,
126 htonl(byteorder->len));
127 }
128 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SIZE)) {
129 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SIZE,
130 htonl(byteorder->size));
131 }
132}
133
134static int
135nftnl_expr_byteorder_parse(struct nftnl_expr *e, struct nlattr *attr)
136{
137 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
138 struct nlattr *tb[NFTA_BYTEORDER_MAX+1] = {};
139 int ret = 0;
140
141 if (mnl_attr_parse_nested(attr, nftnl_expr_byteorder_cb, tb) < 0)
142 return -1;
143
144 if (tb[NFTA_BYTEORDER_SREG]) {
145 byteorder->sreg =
146 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SREG]));
147 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SREG);
148 }
149 if (tb[NFTA_BYTEORDER_DREG]) {
150 byteorder->dreg =
151 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_DREG]));
152 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_DREG);
153 }
154 if (tb[NFTA_BYTEORDER_OP]) {
155 byteorder->op =
156 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_OP]));
157 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_OP);
158 }
159 if (tb[NFTA_BYTEORDER_LEN]) {
160 byteorder->len =
161 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_LEN]));
162 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_LEN);
163 }
164 if (tb[NFTA_BYTEORDER_SIZE]) {
165 byteorder->size =
166 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SIZE]));
167 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SIZE);
168 }
169
170 return ret;
171}
172
173static const char *expr_byteorder_str[] = {
174 [NFT_BYTEORDER_HTON] = "hton",
175 [NFT_BYTEORDER_NTOH] = "ntoh",
176};
177
178static const char *bo2str(uint32_t type)
179{
180 if (type > NFT_BYTEORDER_HTON)
181 return "unknown";
182
183 return expr_byteorder_str[type];
184}
185
186static inline int nftnl_str2ntoh(const char *op)
187{
188 if (strcmp(op, "ntoh") == 0)
189 return NFT_BYTEORDER_NTOH;
190 else if (strcmp(op, "hton") == 0)
191 return NFT_BYTEORDER_HTON;
192 else {
193 errno = EINVAL;
194 return -1;
195 }
196}
197
198static int
199nftnl_expr_byteorder_snprintf(char *buf, size_t remain,
200 uint32_t flags, const struct nftnl_expr *e)
201{
202 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
203 int offset = 0, ret;
204
205 ret = snprintf(buf, remain, "reg %u = %s(reg %u, %u, %u) ",
206 byteorder->dreg, bo2str(byteorder->op),
207 byteorder->sreg, byteorder->size, byteorder->len);
208 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
209
210 return offset;
211}
212
213static struct attr_policy byteorder_attr_policy[__NFTNL_EXPR_BYTEORDER_MAX] = {
214 [NFTNL_EXPR_BYTEORDER_DREG] = { .maxlen = sizeof(uint32_t) },
215 [NFTNL_EXPR_BYTEORDER_SREG] = { .maxlen = sizeof(uint32_t) },
216 [NFTNL_EXPR_BYTEORDER_OP] = { .maxlen = sizeof(uint32_t) },
217 [NFTNL_EXPR_BYTEORDER_LEN] = { .maxlen = sizeof(uint32_t) },
218 [NFTNL_EXPR_BYTEORDER_SIZE] = { .maxlen = sizeof(uint32_t) },
219};
220
221struct expr_ops expr_ops_byteorder = {
222 .name = "byteorder",
223 .alloc_len = sizeof(struct nftnl_expr_byteorder),
224 .nftnl_max_attr = __NFTNL_EXPR_BYTEORDER_MAX - 1,
225 .attr_policy = byteorder_attr_policy,
226 .set = nftnl_expr_byteorder_set,
227 .get = nftnl_expr_byteorder_get,
228 .parse = nftnl_expr_byteorder_parse,
229 .build = nftnl_expr_byteorder_build,
230 .output = nftnl_expr_byteorder_snprintf,
231};