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6#include <linux/export.h>
7#include <net/ipv6.h>
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12
13bool ipv6_ext_hdr(u8 nexthdr)
14{
15
16
17
18 return (nexthdr == NEXTHDR_HOP) ||
19 (nexthdr == NEXTHDR_ROUTING) ||
20 (nexthdr == NEXTHDR_FRAGMENT) ||
21 (nexthdr == NEXTHDR_AUTH) ||
22 (nexthdr == NEXTHDR_NONE) ||
23 (nexthdr == NEXTHDR_DEST);
24}
25EXPORT_SYMBOL(ipv6_ext_hdr);
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72int ipv6_skip_exthdr(const struct sk_buff *skb, int start, u8 *nexthdrp,
73 __be16 *frag_offp)
74{
75 u8 nexthdr = *nexthdrp;
76
77 *frag_offp = 0;
78
79 while (ipv6_ext_hdr(nexthdr)) {
80 struct ipv6_opt_hdr _hdr, *hp;
81 int hdrlen;
82
83 if (nexthdr == NEXTHDR_NONE)
84 return -1;
85 hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
86 if (!hp)
87 return -1;
88 if (nexthdr == NEXTHDR_FRAGMENT) {
89 __be16 _frag_off, *fp;
90 fp = skb_header_pointer(skb,
91 start+offsetof(struct frag_hdr,
92 frag_off),
93 sizeof(_frag_off),
94 &_frag_off);
95 if (!fp)
96 return -1;
97
98 *frag_offp = *fp;
99 if (ntohs(*frag_offp) & ~0x7)
100 break;
101 hdrlen = 8;
102 } else if (nexthdr == NEXTHDR_AUTH)
103 hdrlen = ipv6_authlen(hp);
104 else
105 hdrlen = ipv6_optlen(hp);
106
107 nexthdr = hp->nexthdr;
108 start += hdrlen;
109 }
110
111 *nexthdrp = nexthdr;
112 return start;
113}
114EXPORT_SYMBOL(ipv6_skip_exthdr);
115
116int ipv6_find_tlv(const struct sk_buff *skb, int offset, int type)
117{
118 const unsigned char *nh = skb_network_header(skb);
119 int packet_len = skb_tail_pointer(skb) - skb_network_header(skb);
120 struct ipv6_opt_hdr *hdr;
121 int len;
122
123 if (offset + 2 > packet_len)
124 goto bad;
125 hdr = (struct ipv6_opt_hdr *)(nh + offset);
126 len = ((hdr->hdrlen + 1) << 3);
127
128 if (offset + len > packet_len)
129 goto bad;
130
131 offset += 2;
132 len -= 2;
133
134 while (len > 0) {
135 int opttype = nh[offset];
136 int optlen;
137
138 if (opttype == type)
139 return offset;
140
141 switch (opttype) {
142 case IPV6_TLV_PAD1:
143 optlen = 1;
144 break;
145 default:
146 optlen = nh[offset + 1] + 2;
147 if (optlen > len)
148 goto bad;
149 break;
150 }
151 offset += optlen;
152 len -= optlen;
153 }
154
155 bad:
156 return -1;
157}
158EXPORT_SYMBOL_GPL(ipv6_find_tlv);
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186int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset,
187 int target, unsigned short *fragoff, int *flags)
188{
189 unsigned int start = skb_network_offset(skb) + sizeof(struct ipv6hdr);
190 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
191 bool found;
192
193 if (fragoff)
194 *fragoff = 0;
195
196 if (*offset) {
197 struct ipv6hdr _ip6, *ip6;
198
199 ip6 = skb_header_pointer(skb, *offset, sizeof(_ip6), &_ip6);
200 if (!ip6 || (ip6->version != 6)) {
201 printk(KERN_ERR "IPv6 header not found\n");
202 return -EBADMSG;
203 }
204 start = *offset + sizeof(struct ipv6hdr);
205 nexthdr = ip6->nexthdr;
206 }
207
208 do {
209 struct ipv6_opt_hdr _hdr, *hp;
210 unsigned int hdrlen;
211 found = (nexthdr == target);
212
213 if ((!ipv6_ext_hdr(nexthdr)) || nexthdr == NEXTHDR_NONE) {
214 if (target < 0 || found)
215 break;
216 return -ENOENT;
217 }
218
219 hp = skb_header_pointer(skb, start, sizeof(_hdr), &_hdr);
220 if (!hp)
221 return -EBADMSG;
222
223 if (nexthdr == NEXTHDR_ROUTING) {
224 struct ipv6_rt_hdr _rh, *rh;
225
226 rh = skb_header_pointer(skb, start, sizeof(_rh),
227 &_rh);
228 if (!rh)
229 return -EBADMSG;
230
231 if (flags && (*flags & IP6_FH_F_SKIP_RH) &&
232 rh->segments_left == 0)
233 found = false;
234 }
235
236 if (nexthdr == NEXTHDR_FRAGMENT) {
237 unsigned short _frag_off;
238 __be16 *fp;
239
240 if (flags)
241 *flags |= IP6_FH_F_FRAG;
242 fp = skb_header_pointer(skb,
243 start+offsetof(struct frag_hdr,
244 frag_off),
245 sizeof(_frag_off),
246 &_frag_off);
247 if (!fp)
248 return -EBADMSG;
249
250 _frag_off = ntohs(*fp) & ~0x7;
251 if (_frag_off) {
252 if (target < 0 &&
253 ((!ipv6_ext_hdr(hp->nexthdr)) ||
254 hp->nexthdr == NEXTHDR_NONE)) {
255 if (fragoff)
256 *fragoff = _frag_off;
257 return hp->nexthdr;
258 }
259 if (!found)
260 return -ENOENT;
261 if (fragoff)
262 *fragoff = _frag_off;
263 break;
264 }
265 hdrlen = 8;
266 } else if (nexthdr == NEXTHDR_AUTH) {
267 if (flags && (*flags & IP6_FH_F_AUTH) && (target < 0))
268 break;
269 hdrlen = ipv6_authlen(hp);
270 } else
271 hdrlen = ipv6_optlen(hp);
272
273 if (!found) {
274 nexthdr = hp->nexthdr;
275 start += hdrlen;
276 }
277 } while (!found);
278
279 *offset = start;
280 return nexthdr;
281}
282EXPORT_SYMBOL(ipv6_find_hdr);
283