libnftnl 1.2.6
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, sizeof(byteorder->sreg));
41 break;
42 case NFTNL_EXPR_BYTEORDER_DREG:
43 memcpy(&byteorder->dreg, data, sizeof(byteorder->dreg));
44 break;
45 case NFTNL_EXPR_BYTEORDER_OP:
46 memcpy(&byteorder->op, data, sizeof(byteorder->op));
47 break;
48 case NFTNL_EXPR_BYTEORDER_LEN:
49 memcpy(&byteorder->len, data, sizeof(byteorder->len));
50 break;
51 case NFTNL_EXPR_BYTEORDER_SIZE:
52 memcpy(&byteorder->size, data, sizeof(byteorder->size));
53 break;
54 default:
55 return -1;
56 }
57 return 0;
58}
59
60static const void *
61nftnl_expr_byteorder_get(const struct nftnl_expr *e, uint16_t type,
62 uint32_t *data_len)
63{
64 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
65
66 switch(type) {
67 case NFTNL_EXPR_BYTEORDER_SREG:
68 *data_len = sizeof(byteorder->sreg);
69 return &byteorder->sreg;
70 case NFTNL_EXPR_BYTEORDER_DREG:
71 *data_len = sizeof(byteorder->dreg);
72 return &byteorder->dreg;
73 case NFTNL_EXPR_BYTEORDER_OP:
74 *data_len = sizeof(byteorder->op);
75 return &byteorder->op;
76 case NFTNL_EXPR_BYTEORDER_LEN:
77 *data_len = sizeof(byteorder->len);
78 return &byteorder->len;
79 case NFTNL_EXPR_BYTEORDER_SIZE:
80 *data_len = sizeof(byteorder->size);
81 return &byteorder->size;
82 }
83 return NULL;
84}
85
86static int nftnl_expr_byteorder_cb(const struct nlattr *attr, void *data)
87{
88 const struct nlattr **tb = data;
89 int type = mnl_attr_get_type(attr);
90
91 if (mnl_attr_type_valid(attr, NFTA_BYTEORDER_MAX) < 0)
92 return MNL_CB_OK;
93
94 switch(type) {
95 case NFTA_BYTEORDER_SREG:
96 case NFTA_BYTEORDER_DREG:
97 case NFTA_BYTEORDER_OP:
98 case NFTA_BYTEORDER_LEN:
99 case NFTA_BYTEORDER_SIZE:
100 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
101 abi_breakage();
102 break;
103 }
104
105 tb[type] = attr;
106 return MNL_CB_OK;
107}
108
109static void
110nftnl_expr_byteorder_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
111{
112 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
113
114 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SREG)) {
115 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SREG,
116 htonl(byteorder->sreg));
117 }
118 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_DREG)) {
119 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_DREG,
120 htonl(byteorder->dreg));
121 }
122 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_OP)) {
123 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_OP,
124 htonl(byteorder->op));
125 }
126 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_LEN)) {
127 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_LEN,
128 htonl(byteorder->len));
129 }
130 if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SIZE)) {
131 mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SIZE,
132 htonl(byteorder->size));
133 }
134}
135
136static int
137nftnl_expr_byteorder_parse(struct nftnl_expr *e, struct nlattr *attr)
138{
139 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
140 struct nlattr *tb[NFTA_BYTEORDER_MAX+1] = {};
141 int ret = 0;
142
143 if (mnl_attr_parse_nested(attr, nftnl_expr_byteorder_cb, tb) < 0)
144 return -1;
145
146 if (tb[NFTA_BYTEORDER_SREG]) {
147 byteorder->sreg =
148 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SREG]));
149 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SREG);
150 }
151 if (tb[NFTA_BYTEORDER_DREG]) {
152 byteorder->dreg =
153 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_DREG]));
154 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_DREG);
155 }
156 if (tb[NFTA_BYTEORDER_OP]) {
157 byteorder->op =
158 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_OP]));
159 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_OP);
160 }
161 if (tb[NFTA_BYTEORDER_LEN]) {
162 byteorder->len =
163 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_LEN]));
164 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_LEN);
165 }
166 if (tb[NFTA_BYTEORDER_SIZE]) {
167 byteorder->size =
168 ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SIZE]));
169 e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SIZE);
170 }
171
172 return ret;
173}
174
175static const char *expr_byteorder_str[] = {
176 [NFT_BYTEORDER_HTON] = "hton",
177 [NFT_BYTEORDER_NTOH] = "ntoh",
178};
179
180static const char *bo2str(uint32_t type)
181{
182 if (type > NFT_BYTEORDER_HTON)
183 return "unknown";
184
185 return expr_byteorder_str[type];
186}
187
188static inline int nftnl_str2ntoh(const char *op)
189{
190 if (strcmp(op, "ntoh") == 0)
191 return NFT_BYTEORDER_NTOH;
192 else if (strcmp(op, "hton") == 0)
193 return NFT_BYTEORDER_HTON;
194 else {
195 errno = EINVAL;
196 return -1;
197 }
198}
199
200static int
201nftnl_expr_byteorder_snprintf(char *buf, size_t remain,
202 uint32_t flags, const struct nftnl_expr *e)
203{
204 struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
205 int offset = 0, ret;
206
207 ret = snprintf(buf, remain, "reg %u = %s(reg %u, %u, %u) ",
208 byteorder->dreg, bo2str(byteorder->op),
209 byteorder->sreg, byteorder->size, byteorder->len);
210 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
211
212 return offset;
213}
214
215struct expr_ops expr_ops_byteorder = {
216 .name = "byteorder",
217 .alloc_len = sizeof(struct nftnl_expr_byteorder),
218 .max_attr = NFTA_BYTEORDER_MAX,
219 .set = nftnl_expr_byteorder_set,
220 .get = nftnl_expr_byteorder_get,
221 .parse = nftnl_expr_byteorder_parse,
222 .build = nftnl_expr_byteorder_build,
223 .output = nftnl_expr_byteorder_snprintf,
224};