libnftnl  1.2.8
flow_offload.c
1 #include "internal.h"
2 
3 #include <stdio.h>
4 #include <stdint.h>
5 #include <string.h> /* for memcpy */
6 #include <arpa/inet.h>
7 #include <errno.h>
8 #include <libmnl/libmnl.h>
9 #include <linux/netfilter/nf_tables.h>
10 #include <libnftnl/rule.h>
11 #include <libnftnl/expr.h>
12 
14  char *table_name;
15 };
16 
17 static int nftnl_expr_flow_set(struct nftnl_expr *e, uint16_t type,
18  const void *data, uint32_t data_len)
19 {
20  struct nftnl_expr_flow *flow = nftnl_expr_data(e);
21 
22  switch (type) {
23  case NFTNL_EXPR_FLOW_TABLE_NAME:
24  flow->table_name = strdup((const char *)data);
25  if (!flow->table_name)
26  return -1;
27  break;
28  }
29  return 0;
30 }
31 
32 static const void *nftnl_expr_flow_get(const struct nftnl_expr *e,
33  uint16_t type, uint32_t *data_len)
34 {
35  struct nftnl_expr_flow *flow = nftnl_expr_data(e);
36 
37  switch(type) {
38  case NFTNL_EXPR_FLOW_TABLE_NAME:
39  *data_len = strlen(flow->table_name) + 1;
40  return flow->table_name;
41  }
42  return NULL;
43 }
44 
45 static int nftnl_expr_flow_cb(const struct nlattr *attr, void *data)
46 {
47  const struct nlattr **tb = data;
48  int type = mnl_attr_get_type(attr);
49 
50  if (mnl_attr_type_valid(attr, NFTA_FLOW_MAX) < 0)
51  return MNL_CB_OK;
52 
53  switch(type) {
54  case NFTA_FLOW_TABLE_NAME:
55  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
56  abi_breakage();
57  break;
58  }
59 
60  tb[type] = attr;
61  return MNL_CB_OK;
62 }
63 
64 static void nftnl_expr_flow_build(struct nlmsghdr *nlh,
65  const struct nftnl_expr *e)
66 {
67  struct nftnl_expr_flow *flow = nftnl_expr_data(e);
68 
69  if (e->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
70  mnl_attr_put_strz(nlh, NFTA_FLOW_TABLE_NAME, flow->table_name);
71 }
72 
73 static int nftnl_expr_flow_parse(struct nftnl_expr *e, struct nlattr *attr)
74 {
75  struct nftnl_expr_flow *flow = nftnl_expr_data(e);
76  struct nlattr *tb[NFTA_FLOW_MAX+1] = {};
77  int ret = 0;
78 
79  if (mnl_attr_parse_nested(attr, nftnl_expr_flow_cb, tb) < 0)
80  return -1;
81 
82  if (tb[NFTA_FLOW_TABLE_NAME]) {
83  flow->table_name =
84  strdup(mnl_attr_get_str(tb[NFTA_FLOW_TABLE_NAME]));
85  if (!flow->table_name)
86  return -1;
87  e->flags |= (1 << NFTNL_EXPR_FLOW_TABLE_NAME);
88  }
89 
90  return ret;
91 }
92 
93 static int nftnl_expr_flow_snprintf(char *buf, size_t remain,
94  uint32_t flags, const struct nftnl_expr *e)
95 {
96  struct nftnl_expr_flow *l = nftnl_expr_data(e);
97  int offset = 0, ret;
98 
99  ret = snprintf(buf, remain, "flowtable %s ", l->table_name);
100  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
101 
102  return offset;
103 }
104 
105 static void nftnl_expr_flow_free(const struct nftnl_expr *e)
106 {
107  struct nftnl_expr_flow *flow = nftnl_expr_data(e);
108 
109  xfree(flow->table_name);
110 }
111 
112 static struct attr_policy flow_offload_attr_policy[__NFTNL_EXPR_FLOW_MAX] = {
113  [NFTNL_EXPR_FLOW_TABLE_NAME] = { .maxlen = NFT_NAME_MAXLEN },
114 };
115 
116 struct expr_ops expr_ops_flow = {
117  .name = "flow_offload",
118  .alloc_len = sizeof(struct nftnl_expr_flow),
119  .nftnl_max_attr = __NFTNL_EXPR_FLOW_MAX - 1,
120  .attr_policy = flow_offload_attr_policy,
121  .free = nftnl_expr_flow_free,
122  .set = nftnl_expr_flow_set,
123  .get = nftnl_expr_flow_get,
124  .parse = nftnl_expr_flow_parse,
125  .build = nftnl_expr_flow_build,
126  .output = nftnl_expr_flow_snprintf,
127 };