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74 lines
1.4 KiB
74 lines
1.4 KiB
#include "rtplib.h"
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#include <arpa/inet.h>
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#include "str.h"
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#include "log.h"
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struct rtp_extension {
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u_int16_t undefined;
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u_int16_t length;
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} __attribute__ ((packed));
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int rtp_payload(struct rtp_header **out, str *p, const str *s) {
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struct rtp_header *rtp;
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struct rtp_extension *ext;
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const char *err;
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err = "short packet (header)";
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if (s->len < sizeof(*rtp))
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goto error;
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rtp = (void *) s->s;
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err = "invalid header version";
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if ((rtp->v_p_x_cc & 0xc0) != 0x80) /* version 2 */
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goto error;
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if (!p)
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goto done;
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*p = *s;
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/* fixed header */
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str_shift(p, sizeof(*rtp));
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/* csrc list */
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err = "short packet (CSRC list)";
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if (str_shift(p, (rtp->v_p_x_cc & 0xf) * 4))
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goto error;
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if ((rtp->v_p_x_cc & 0x10)) {
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/* extension */
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err = "short packet (extension header)";
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if (p->len < sizeof(*ext))
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goto error;
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ext = (void *) p->s;
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err = "short packet (header extensions)";
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if (str_shift(p, 4 + ntohs(ext->length) * 4))
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goto error;
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}
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done:
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*out = rtp;
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return 0;
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error:
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ilog(LOG_WARNING | LOG_FLAG_LIMIT, "Error parsing RTP header: %s", err);
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return -1;
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}
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int rtp_padding(struct rtp_header *header, str *payload) {
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if (!(header->v_p_x_cc & 0x20))
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return 0; // no padding
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if (payload->len == 0)
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return -1;
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unsigned int padding = (unsigned char) payload->s[payload->len - 1];
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if (payload->len < padding)
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return -1;
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payload->len -= padding;
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return 0;
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}
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