/* 查找密文 */
static ngx_int_t
ngx_rtmp_find_digest(ngx_buf_t *b, ngx_str_t *key, size_t base, ngx_log_t *log)
{
size_t n, offs;
u_char digest[NGX_RTMP_HANDSHAKE_KEYLEN];
u_char *p;
/* 获得密文偏移 */
offs = 0;
for (n = 0; n < 4; ++n) {
offs += b->pos[base + n];
}
offs = (offs % 728) + base + 4;
p = b->pos + offs;
if (ngx_rtmp_make_digest(key, b, p, digest, log) != NGX_OK) {
return NGX_ERROR;
}
/* 比较是否一致 */
if (ngx_memcmp(digest, p, NGX_RTMP_HANDSHAKE_KEYLEN) == 0) {
return offs;
}
return NGX_ERROR;
}
static ngx_int_t
ngx_rtmp_handshake_parse_challenge(ngx_rtmp_session_t *s,
ngx_str_t *peer_key, ngx_str_t *key)
{
ngx_buf_t *b;
u_char *p;
ngx_int_t offs;
b = s->hs_buf;
if (*b->pos != '\x03') {
ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
"handshake: unexpected RTMP version: %i",
(ngx_int_t)*b->pos);
return NGX_ERROR;
}
++b->pos;
s->peer_epoch = 0;
ngx_rtmp_rmemcpy(&s->peer_epoch, b->pos, 4);
p = b->pos + 4;
ngx_log_debug5(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
"handshake: peer version=%i.%i.%i.%i epoch=%uD",
(ngx_int_t)p[3], (ngx_int_t)p[2],
(ngx_int_t)p[1], (ngx_int_t)p[0],
(uint32_t)s->peer_epoch);
if (*(uint32_t *)p == 0) {
s->hs_old = 1;
return NGX_OK;
}
offs = ngx_rtmp_find_digest(b, peer_key, 772, s->connection->log);
if (offs == NGX_ERROR) {
offs = ngx_rtmp_find_digest(b, peer_key, 8, s->connection->log);
}
if (offs == NGX_ERROR) {
ngx_log_error(NGX_LOG_INFO, s->connection->log, 0,
"handshake: digest not found");
s->hs_old = 1;
return NGX_OK;
}
ngx_log_debug1(NGX_LOG_DEBUG_RTMP, s->connection->log, 0,
"handshake: digest found at pos=%i", offs);
b->pos += offs;
b->last = b->pos + NGX_RTMP_HANDSHAKE_KEYLEN;
/* 获得密文 */
s->hs_digest = ngx_palloc(s->connection->pool, NGX_RTMP_HANDSHAKE_KEYLEN);
if (ngx_rtmp_make_digest(key, b, NULL, s->hs_digest, s->connection->log)
!= NGX_OK)
{
return NGX_ERROR;
}
return NGX_OK;
}
static ngx_int_t
ngx_rtmp_write_digest(ngx_buf_t *b, ngx_str_t *key, size_t base,
ngx_log_t *log)
{
size_t n, offs;
u_char *p;
offs = 0;
for (n = 8; n < 12; ++n) {
offs += b->pos[base + n];
}
offs = (offs % 728) + base + 12;
p = b->pos + offs;
if (ngx_rtmp_make_digest(key, b, p, p, log) != NGX_OK) {
return NGX_ERROR;
}
return NGX_OK;
}
static ngx_int_t
ngx_rtmp_handshake_create_response(ngx_rtmp_session_t *s)
{
ngx_buf_t *b;
u_char *p;
ngx_str_t key;
b = s->hs_buf;
b->pos = b->last = b->start + 1;
ngx_rtmp_fill_random_buffer(b);
if (s->hs_digest) {
p = b->last - NGX_RTMP_HANDSHAKE_KEYLEN;
key.data = s->hs_digest;
key.len = NGX_RTMP_HANDSHAKE_KEYLEN;
if (ngx_rtmp_make_digest(&key, b, p, p, s->connection->log) != NGX_OK) {
return NGX_ERROR;
}
}
return NGX_OK;
}
