Linux 2.6.31.6
[linux/fpc-iii.git] / net / netfilter / xt_sctp.c
bloba189ada9128f523e9481f5c4d9c6c993c9574bad
1 #include <linux/module.h>
2 #include <linux/skbuff.h>
3 #include <net/ip.h>
4 #include <net/ipv6.h>
5 #include <linux/sctp.h>
7 #include <linux/netfilter/x_tables.h>
8 #include <linux/netfilter/xt_sctp.h>
9 #include <linux/netfilter_ipv4/ip_tables.h>
10 #include <linux/netfilter_ipv6/ip6_tables.h>
12 MODULE_LICENSE("GPL");
13 MODULE_AUTHOR("Kiran Kumar Immidi");
14 MODULE_DESCRIPTION("Xtables: SCTP protocol packet match");
15 MODULE_ALIAS("ipt_sctp");
16 MODULE_ALIAS("ip6t_sctp");
18 #ifdef DEBUG_SCTP
19 #define duprintf(format, args...) printk(format , ## args)
20 #else
21 #define duprintf(format, args...)
22 #endif
24 #define SCCHECK(cond, option, flag, invflag) (!((flag) & (option)) \
25 || (!!((invflag) & (option)) ^ (cond)))
27 static bool
28 match_flags(const struct xt_sctp_flag_info *flag_info,
29 const int flag_count,
30 u_int8_t chunktype,
31 u_int8_t chunkflags)
33 int i;
35 for (i = 0; i < flag_count; i++)
36 if (flag_info[i].chunktype == chunktype)
37 return (chunkflags & flag_info[i].flag_mask) == flag_info[i].flag;
39 return true;
42 static inline bool
43 match_packet(const struct sk_buff *skb,
44 unsigned int offset,
45 const struct xt_sctp_info *info,
46 bool *hotdrop)
48 u_int32_t chunkmapcopy[256 / sizeof (u_int32_t)];
49 const sctp_chunkhdr_t *sch;
50 sctp_chunkhdr_t _sch;
51 int chunk_match_type = info->chunk_match_type;
52 const struct xt_sctp_flag_info *flag_info = info->flag_info;
53 int flag_count = info->flag_count;
55 #ifdef DEBUG_SCTP
56 int i = 0;
57 #endif
59 if (chunk_match_type == SCTP_CHUNK_MATCH_ALL)
60 SCTP_CHUNKMAP_COPY(chunkmapcopy, info->chunkmap);
62 do {
63 sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch);
64 if (sch == NULL || sch->length == 0) {
65 duprintf("Dropping invalid SCTP packet.\n");
66 *hotdrop = true;
67 return false;
70 duprintf("Chunk num: %d\toffset: %d\ttype: %d\tlength: %d\tflags: %x\n",
71 ++i, offset, sch->type, htons(sch->length), sch->flags);
73 offset += (ntohs(sch->length) + 3) & ~3;
75 duprintf("skb->len: %d\toffset: %d\n", skb->len, offset);
77 if (SCTP_CHUNKMAP_IS_SET(info->chunkmap, sch->type)) {
78 switch (chunk_match_type) {
79 case SCTP_CHUNK_MATCH_ANY:
80 if (match_flags(flag_info, flag_count,
81 sch->type, sch->flags)) {
82 return true;
84 break;
86 case SCTP_CHUNK_MATCH_ALL:
87 if (match_flags(flag_info, flag_count,
88 sch->type, sch->flags))
89 SCTP_CHUNKMAP_CLEAR(chunkmapcopy, sch->type);
90 break;
92 case SCTP_CHUNK_MATCH_ONLY:
93 if (!match_flags(flag_info, flag_count,
94 sch->type, sch->flags))
95 return false;
96 break;
98 } else {
99 switch (chunk_match_type) {
100 case SCTP_CHUNK_MATCH_ONLY:
101 return false;
104 } while (offset < skb->len);
106 switch (chunk_match_type) {
107 case SCTP_CHUNK_MATCH_ALL:
108 return SCTP_CHUNKMAP_IS_CLEAR(chunkmapcopy);
109 case SCTP_CHUNK_MATCH_ANY:
110 return false;
111 case SCTP_CHUNK_MATCH_ONLY:
112 return true;
115 /* This will never be reached, but required to stop compiler whine */
116 return false;
119 static bool
120 sctp_mt(const struct sk_buff *skb, const struct xt_match_param *par)
122 const struct xt_sctp_info *info = par->matchinfo;
123 const sctp_sctphdr_t *sh;
124 sctp_sctphdr_t _sh;
126 if (par->fragoff != 0) {
127 duprintf("Dropping non-first fragment.. FIXME\n");
128 return false;
131 sh = skb_header_pointer(skb, par->thoff, sizeof(_sh), &_sh);
132 if (sh == NULL) {
133 duprintf("Dropping evil TCP offset=0 tinygram.\n");
134 *par->hotdrop = true;
135 return false;
137 duprintf("spt: %d\tdpt: %d\n", ntohs(sh->source), ntohs(sh->dest));
139 return SCCHECK(ntohs(sh->source) >= info->spts[0]
140 && ntohs(sh->source) <= info->spts[1],
141 XT_SCTP_SRC_PORTS, info->flags, info->invflags)
142 && SCCHECK(ntohs(sh->dest) >= info->dpts[0]
143 && ntohs(sh->dest) <= info->dpts[1],
144 XT_SCTP_DEST_PORTS, info->flags, info->invflags)
145 && SCCHECK(match_packet(skb, par->thoff + sizeof(sctp_sctphdr_t),
146 info, par->hotdrop),
147 XT_SCTP_CHUNK_TYPES, info->flags, info->invflags);
150 static bool sctp_mt_check(const struct xt_mtchk_param *par)
152 const struct xt_sctp_info *info = par->matchinfo;
154 return !(info->flags & ~XT_SCTP_VALID_FLAGS)
155 && !(info->invflags & ~XT_SCTP_VALID_FLAGS)
156 && !(info->invflags & ~info->flags)
157 && ((!(info->flags & XT_SCTP_CHUNK_TYPES)) ||
158 (info->chunk_match_type &
159 (SCTP_CHUNK_MATCH_ALL
160 | SCTP_CHUNK_MATCH_ANY
161 | SCTP_CHUNK_MATCH_ONLY)));
164 static struct xt_match sctp_mt_reg[] __read_mostly = {
166 .name = "sctp",
167 .family = NFPROTO_IPV4,
168 .checkentry = sctp_mt_check,
169 .match = sctp_mt,
170 .matchsize = sizeof(struct xt_sctp_info),
171 .proto = IPPROTO_SCTP,
172 .me = THIS_MODULE
175 .name = "sctp",
176 .family = NFPROTO_IPV6,
177 .checkentry = sctp_mt_check,
178 .match = sctp_mt,
179 .matchsize = sizeof(struct xt_sctp_info),
180 .proto = IPPROTO_SCTP,
181 .me = THIS_MODULE
185 static int __init sctp_mt_init(void)
187 return xt_register_matches(sctp_mt_reg, ARRAY_SIZE(sctp_mt_reg));
190 static void __exit sctp_mt_exit(void)
192 xt_unregister_matches(sctp_mt_reg, ARRAY_SIZE(sctp_mt_reg));
195 module_init(sctp_mt_init);
196 module_exit(sctp_mt_exit);