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107 lines
1.9 KiB
107 lines
1.9 KiB
#include "stun.h"
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#include <sys/types.h>
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#include "str.h"
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#include "aux.h"
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struct stun {
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u_int16_t msg_type;
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u_int16_t msg_len;
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u_int32_t cookie;
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unsigned char transaction[12];
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} __attribute__ ((packed));
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struct tlv {
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u_int16_t type;
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u_int16_t len;
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char value[0];
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} __attribute__ ((packed));
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struct stun_attrs {
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str username;
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str msg_integrity;
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u_int32_t priority;
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int use:1,
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controlled:1,
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controlling:1;
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};
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static int stun_attributes(struct stun_attrs *out, str *s) {
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struct tlv *tlv;
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int len;
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str attr;
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ZERO(*out);
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while (1) {
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if (!s->len)
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return 0;
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tlv = (void *) s->s;
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if (str_shift(s, sizeof(*tlv)))
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return -1;
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len = ntohs(tlv->len);
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attr = *s;
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attr.len = len;
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len = (len + 3) & 0xfffc;
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if (str_shift(s, len))
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return -1;
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switch (ntohs(tlv->type)) {
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case 0x0006: /* username */
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out->username = attr;
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break;
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case 0x0008: /* message-integrity */
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out->msg_integrity = attr;
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break;
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case 0x0025: /* use-candidate */
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out->use = 1;
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break;
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case 0x8029: /* ice-controlled */
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out->controlled = 1;
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break;
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case 0x802a: /* ice-controlling */
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out->controlling = 1;
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break;
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case 0x0024: /* priority */
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if (attr.len != 4)
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return -1;
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out->priority = ntohl(*((u_int32_t *) attr.s));
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break;
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}
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}
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return 0;
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}
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/* XXX add error reporting */
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int stun(char *buf, int len) {
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struct stun *s = (void *) buf;
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int msglen, method, class;
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str attr_str;
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struct stun_attrs attrs;
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msglen = ntohs(s->msg_len);
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if (msglen + 20 > len || msglen < 0)
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return -1;
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class = method = ntohl(s->msg_type);
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class = ((class & 0x10) >> 4) | ((class & 0x100) >> 7);
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method = (method & 0xf) | ((method & 0xe0) >> 1) | ((method & 0x3e00) >> 2);
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if (method != 0x1) /* binding */
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return -1;
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attr_str.s = &buf[20];
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attr_str.len = len;
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if (stun_attributes(&attrs, &attr_str))
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return -1;
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return 0;
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}
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