rtmp协议分析---HTTP_get分析

在分析rtmpdump源代码时，发现一个http协议，感觉挺有意思的，就摘录下来。

主要是在RTMP_HashSWF函数中看到的。

HTTPResult HTTP_get(struct HTTP_ctx *http, const char *url, HTTP_read_callback *cb){char *host, *path;char *p1, *p2;char hbuf[256];int port = 80;#ifdef CRYPTOint ssl = 0;#endifint hlen, flen = 0;int rc, i;int len_known;HTTPResult ret = HTTPRES_OK;struct sockaddr_in sa;RTMPSockBuf sb = {0};http->status = -1;memset(&sa, 0, sizeof(struct sockaddr_in));sa.sin_family = AF_INET;/* we only handle http here *///判断是否是https or httpif (strncasecmp(url, "http", 4))return HTTPRES_BAD_REQUEST;if (url[4] == 's'){#ifdef CRYPTOssl = 1;port = 443;if (!RTMP_TLS_ctx)RTMP_TLS_Init();#elsereturn HTTPRES_BAD_REQUEST;#endif}p1 = strchr(url + 4, ':');if (!p1 || strncmp(p1, "://", 3))return HTTPRES_BAD_REQUEST;host = p1 + 3;path = strchr(host, '/');hlen = path - host;strncpy(hbuf, host, hlen);hbuf[hlen] = '\0';host = hbuf;p1 = strrchr(host, ':');if (p1){*p1++ = '\0';port = atoi(p1);}sa.sin_addr.s_addr = inet_addr(host);if (sa.sin_addr.s_addr == INADDR_NONE){struct hostent *hp = gethostbyname(host);if (!hp || !hp->h_addr)return HTTPRES_LOST_CONNECTION;sa.sin_addr = *(struct in_addr *)hp->h_addr;}sa.sin_port = htons(port);sb.sb_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if (sb.sb_socket == -1)return HTTPRES_LOST_CONNECTION;i = sprintf(sb.sb_buf, "GET %s HTTP/1.0\r\nUser-Agent: %s\r\nHost: %s\r\nReferrer: %.*s\r\n", path, AGENT, host, (int)(path - url + 1),        url);if (http->date[0])i += sprintf(sb.sb_buf + i, "If-Modified-Since: %s\r\n", http->date);i += sprintf(sb.sb_buf + i, "\r\n");if (connect(sb.sb_socket, (struct sockaddr *)&sa, sizeof(struct sockaddr)) < 0){ret = HTTPRES_LOST_CONNECTION;goto leave;}#ifdef CRYPTOif (ssl){#ifdef NO_SSLRTMP_Log(RTMP_LOGERROR, "%s, No SSL/TLS support", __FUNCTION__);ret = HTTPRES_BAD_REQUEST;goto leave;#elseTLS_client(RTMP_TLS_ctx, sb.sb_ssl);TLS_setfd(sb.sb_ssl, sb.sb_socket);if ((i = TLS_connect(sb.sb_ssl)) < 0){RTMP_Log(RTMP_LOGERROR, "%s, TLS_Connect failed", __FUNCTION__);ret = HTTPRES_LOST_CONNECTION;goto leave;}#endif}#endifRTMPSockBuf_Send(&sb, sb.sb_buf, i);/* set timeout */#define HTTP_TIMEOUT5{SET_RCVTIMEO(tv, HTTP_TIMEOUT);if (setsockopt(sb.sb_socket, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv, sizeof(tv))){RTMP_Log(RTMP_LOGERROR, "%s, Setting socket timeout to %ds failed!", __FUNCTION__, HTTP_TIMEOUT);}}sb.sb_size = 0;sb.sb_timedout = FALSE;if (RTMPSockBuf_Fill(&sb) < 1){ret = HTTPRES_LOST_CONNECTION;goto leave;}if (strncmp(sb.sb_buf, "HTTP/1", 6)){ret = HTTPRES_BAD_REQUEST;goto leave;}p1 = strchr(sb.sb_buf, ' ');rc = atoi(p1 + 1);http->status = rc;if (rc >= 300){if (rc == 304){ret = HTTPRES_OK_NOT_MODIFIED;goto leave;}else if (rc == 404)ret = HTTPRES_NOT_FOUND;else if (rc >= 500)ret = HTTPRES_SERVER_ERROR;else if (rc >= 400)ret = HTTPRES_BAD_REQUEST;elseret = HTTPRES_REDIRECTED;}p1 = memchr(sb.sb_buf, '\n', sb.sb_size);if (!p1){ret = HTTPRES_BAD_REQUEST;goto leave;}sb.sb_start = p1 + 1;sb.sb_size -= sb.sb_start - sb.sb_buf;while ((p2 = memchr(sb.sb_start, '\r', sb.sb_size))){if (*sb.sb_start == '\r'){sb.sb_start += 2;sb.sb_size -= 2;break;}else if (!strncasecmp(sb.sb_start, "Content-Length: ", sizeof("Content-Length: ") - 1)){flen = atoi(sb.sb_start + sizeof("Content-Length: ") - 1);}else if (!strncasecmp(sb.sb_start, "Last-Modified: ", sizeof("Last-Modified: ") - 1)){*p2 = '\0';strcpy(http->date, sb.sb_start + sizeof("Last-Modified: ") - 1);}p2 += 2;sb.sb_size -= p2 - sb.sb_start;sb.sb_start = p2;if (sb.sb_size < 1){if (RTMPSockBuf_Fill(&sb) < 1){ret = HTTPRES_LOST_CONNECTION;goto leave;}}}len_known = flen > 0;while ((!len_known || flen > 0) && (sb.sb_size > 0 || RTMPSockBuf_Fill(&sb) > 0)){cb(sb.sb_start, 1, sb.sb_size, http->data);if (len_known)flen -= sb.sb_size;http->size += sb.sb_size;sb.sb_size = 0;}if (flen > 0)ret = HTTPRES_LOST_CONNECTION;leave: RTMPSockBuf_Close(&sb);return ret;}

回调函数中：

static size_t swfcrunch(void *ptr, size_t size, size_t nmemb, void *stream){struct info *i = stream;char *p = ptr;size_t len = size * nmemb;if (i->first){i->first = 0;/* compressed? */if (!strncmp(p, "CWS", 3)){*p = 'F';i->zlib = 1;}HMAC_crunch(i->ctx, (unsigned char * )p, 8);p += 8;len -= 8;i->size = 8;}if (i->zlib){unsigned char out[CHUNK];i->zs->next_in = (unsigned char *)p;i->zs->avail_in = len;do{i->zs->avail_out = CHUNK;i->zs->next_out = out;inflate(i->zs, Z_NO_FLUSH);len = CHUNK - i->zs->avail_out;i->size += len;HMAC_crunch(i->ctx, out, len);} while (i->zs->avail_out == 0);}else{i->size += len;HMAC_crunch(i->ctx, (unsigned char * )p, len);}return size * nmemb;}

看了一个，跟我之前写的很相似，可以用于以后的参考