libnetfilter_conntrack  1.0.9
expect/parse_mnl.c
1 /*
2  * (C) 2005-2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License as published by
6  * 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 Vyatta Inc. <http://www.vyatta.com>
10  */
11 
12 #include "internal/internal.h"
13 #include <assert.h>
14 #include <libmnl/libmnl.h>
15 
16 static int nlmsg_parse_expection_attr_cb(const struct nlattr *attr, void *data)
17 {
18  const struct nlattr **tb = data;
19  int type = mnl_attr_get_type(attr);
20 
21  /* skip unsupported attribute in user-space */
22  if (mnl_attr_type_valid(attr, CTA_EXPECT_MAX) < 0)
23  return MNL_CB_OK;
24 
25  switch(type) {
26  case CTA_EXPECT_MASTER:
27  case CTA_EXPECT_TUPLE:
28  case CTA_EXPECT_MASK:
29  if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
30  abi_breakage();
31  break;
32  case CTA_EXPECT_TIMEOUT:
33  case CTA_EXPECT_FLAGS:
34  case CTA_EXPECT_ID:
35  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
36  abi_breakage();
37  break;
38  case CTA_EXPECT_HELP_NAME:
39  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
40  abi_breakage();
41  break;
42  case CTA_EXPECT_ZONE:
43  if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
44  abi_breakage();
45  break;
46  }
47  tb[type] = attr;
48  return MNL_CB_OK;
49 }
50 
51 static int nfexp_nlmsg_parse_nat_attr_cb(const struct nlattr *attr, void *data)
52 {
53  int type = mnl_attr_get_type(attr);
54  const struct nlattr **tb = data;
55 
56  if (mnl_attr_type_valid(attr, CTA_MAX) < 0)
57  return MNL_CB_OK;
58 
59  switch(type) {
60  case CTA_EXPECT_NAT_TUPLE:
61  if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
62  abi_breakage();
63  break;
64  case CTA_EXPECT_NAT_DIR:
65  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
66  abi_breakage();
67  break;
68  }
69 
70  tb[type] = attr;
71  return MNL_CB_OK;
72 }
73 
74 static void nfexp_nlmsg_parse_nat(struct nfgenmsg *nfg,
75  const struct nlattr *attr,
76  struct nf_expect *exp)
77 {
78  struct nlattr *tb[CTA_EXPECT_NAT_MAX + 1] = {};
79 
80  if (mnl_attr_parse_nested(attr, nfexp_nlmsg_parse_nat_attr_cb, tb) < 0)
81  return;
82 
83  exp->nat.orig.l3protonum = nfg->nfgen_family;
84  set_bit(ATTR_ORIG_L3PROTO, exp->nat.set);
85 
86  if (tb[CTA_EXPECT_NAT_TUPLE]) {
87  nfct_parse_tuple(tb[CTA_EXPECT_NAT_TUPLE], &exp->nat.orig,
88  __DIR_ORIG, exp->nat.set);
89  set_bit(ATTR_EXP_NAT_TUPLE, exp->set);
90  }
91  if (tb[CTA_EXPECT_NAT_DIR]) {
92  exp->nat_dir =
93  ntohl(mnl_attr_get_u32(tb[CTA_EXPECT_NAT_DIR]));
94  set_bit(ATTR_EXP_NAT_DIR, exp->set);
95  }
96 }
97 
98 int nfexp_nlmsg_parse(const struct nlmsghdr *nlh, struct nf_expect *exp)
99 {
100  struct nlattr *tb[CTA_EXPECT_MAX+1] = {};
101  struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
102 
103  mnl_attr_parse(nlh, sizeof(struct nfgenmsg),
104  nlmsg_parse_expection_attr_cb, tb);
105 
106  if (tb[CTA_EXPECT_MASTER]) {
107  exp->expected.orig.l3protonum = nfg->nfgen_family;
108  set_bit(ATTR_ORIG_L3PROTO, exp->expected.set);
109 
110  nfct_parse_tuple(tb[CTA_EXPECT_MASTER], &exp->master.orig,
111  __DIR_ORIG, exp->master.set);
112  set_bit(ATTR_EXP_MASTER, exp->set);
113  }
114  if (tb[CTA_EXPECT_TUPLE]) {
115  exp->mask.orig.l3protonum = nfg->nfgen_family;
116  set_bit(ATTR_ORIG_L3PROTO, exp->mask.set);
117 
118  nfct_parse_tuple(tb[CTA_EXPECT_TUPLE], &exp->expected.orig,
119  __DIR_ORIG, exp->expected.set);
120  set_bit(ATTR_EXP_EXPECTED, exp->set);
121  }
122  if (tb[CTA_EXPECT_MASK]) {
123  exp->master.orig.l3protonum = nfg->nfgen_family;
124  set_bit(ATTR_ORIG_L3PROTO, exp->master.set);
125 
126  nfct_parse_tuple(tb[CTA_EXPECT_MASK], &exp->mask.orig,
127  __DIR_ORIG, exp->mask.set);
128  set_bit(ATTR_EXP_MASK, exp->set);
129  }
130  if (tb[CTA_EXPECT_TIMEOUT]) {
131  exp->timeout = ntohl(mnl_attr_get_u32(tb[CTA_EXPECT_TIMEOUT]));
132  set_bit(ATTR_EXP_TIMEOUT, exp->set);
133  }
134  if (tb[CTA_EXPECT_ZONE]) {
135  exp->zone = ntohs(mnl_attr_get_u16(tb[CTA_EXPECT_ZONE]));
136  set_bit(ATTR_EXP_ZONE, exp->set);
137  }
138  if (tb[CTA_EXPECT_FLAGS]) {
139  exp->flags = ntohl(mnl_attr_get_u32(tb[CTA_EXPECT_FLAGS]));
140  set_bit(ATTR_EXP_FLAGS, exp->set);
141  }
142  if (tb[CTA_EXPECT_HELP_NAME]) {
143  snprintf(exp->helper_name, NFCT_HELPER_NAME_MAX, "%s",
144  mnl_attr_get_str(tb[CTA_EXPECT_HELP_NAME]));
145  set_bit(ATTR_EXP_HELPER_NAME, exp->set);
146  }
147  if (tb[CTA_EXPECT_CLASS]) {
148  exp->class = ntohl(mnl_attr_get_u32(tb[CTA_EXPECT_CLASS]));
149  set_bit(ATTR_EXP_CLASS, exp->set);
150  }
151  if (tb[CTA_EXPECT_NAT])
152  nfexp_nlmsg_parse_nat(nfg, tb[CTA_EXPECT_NAT], exp);
153 
154  if (tb[CTA_EXPECT_FN]) {
155  int len = mnl_attr_get_payload_len(tb[CTA_EXPECT_FN]);
156  /* the kernel doesn't impose a max length on this str */
157  assert(len <= __NFCT_EXPECTFN_MAX);
158  snprintf(exp->expectfn, __NFCT_EXPECTFN_MAX, "%s",
159  (char *)mnl_attr_get_payload(tb[CTA_EXPECT_FN]));
160  set_bit(ATTR_EXP_FN, exp->set);
161  }
162 
163  return 0;
164 }