live555的發展歷史實在是非常悠久,保守估計已經發展了至少18年以上了,同時,這也導致了live555在很多架構和考慮上面不能滿足現代化的多線程、ipv6方面的需求,雖然官方也開啓了對ipv6功能支持的衆籌,但是已經很久了,預計很長時間內是不會有這個計劃支持了,因爲要改動的地方還真是蠻多的:
今天我們要來聊一下我們在live555擴展IPv6方面是怎麼做到的!
設計過程
-
IPV4 地址
rtsp://192.168.1.100:554/ch1
rtsp://admin:[email protected]:554/ch1 -
IPV6 地址
rtsp://[2001:0:9d38:953c:38b0:d177:88d8:a5e0]:554/ch1
rtsp://admin:12345@[2001:0:9d38:953c:38b0:d177:88d8:a5e0]:554/ch1 -
支持IPv6修改步驟
增加live_ipv4_ipv6.h和live_ipv4_ipv6.cpp兩個文件
用途: 在live所有用到類型爲netAddressBits的文件中,包含該頭文件,針對ipv4和ipv6進行不同的處理;
-
live_ipv4_ipv6.h
#ifndef __LIVE_IPV4_IPV6
#define __LIVE_IPV4_IPV6typedef enum LIVE_IPVER_ENUM
{
LIVE_IP_VER_4 = 0,
LIVE_IP_VER_6
}LIVE_IP_VER_ENUM;extern LIVE_IP_VER_ENUM live_ip_ver;
#endif
-
live_ipv4_ipv6.cpp
#include “live_ipv4_ipv6.h”
LIVE_IP_VER_ENUM live_ip_ver = LIVE_IP_VER_6; -
NetAddress.hh
增加以下定義, 並註釋掉typedef u_int32_t netAddressBits;
typedef struct __LIVE_NET_ADDRESS_INADDR
{
struct in_addr sin_addr;
struct in6_addr sin6_addr;
__LIVE_NET_ADDRESS_INADDR()
{
sin_addr.s_addr = INADDR_ANY;
sin6_addr = in6addr_any;
};
}LIVE_NET_ADDRESS_INADDR;
//typedef u_int32_t netAddressBits; //註釋掉該句,在所有用到netAddressBits的地方,均用LIVE_NET_ADDRESS_INADDR替代;
//增加以下定義
typedef struct __LIVE_NET_ADDRESS_SOCKADDR_IN
{
struct sockaddr_in saddr4;
struct sockaddr_in6 saddr6;
}LIVE_NET_ADDRESS_SOCKADDR_IN;
將所有struct in_addr 改爲 LIVE_NET_ADDRESS, 除了以下幾處:
void AddressString::init(struct in_addr addr)
將所有struct sockaddr_in 改爲 LIVE_NET_ADDRESS_SOCKADDR_IN;
在EasyRTSPClient的live555中,將調用到LIVE_NET_ADDRESS_SOCKADDR_IN的函數,增加一個參數,用於標識是IPv4還是IPv6;
從調用以下代碼開始,進行區分,用於標識該客戶端需要使用IPv4還是IPv6進行連接;
Boolean RTSPClient::parseRTSPURL(UsageEnvironment& env, char const* url,
char*& username, char*& password,
NetAddress& address,
portNumBits& portNum,
char const** urlSuffix) {
do {
// Parse the URL as "rtsp://[<username>[:<password>]@]<server-address-or-name>[:<port>][/<stream-name>]"
char const* prefix = "rtsp://";
unsigned const prefixLength = 7;
if (_strncasecmp(url, prefix, prefixLength) != 0) {
env.setResultMsg("URL is not of the form \"", prefix, "\"");
break;
}
unsigned const parseBufferSize = 100;
char parseBuffer[parseBufferSize] = {0};
char const* from = &url[prefixLength];
// Check whether "<username>[:<password>]@" occurs next.
// We do this by checking whether '@' appears before the end of the URL, or before the first '/'.
username = password = NULL; // default return values
char const* colonPasswordStart = NULL;
char const* p;
//此處檢查字符[
for (p = from; *p != '\0' && *p != '/' && *p != '['; ++p) {
if (*p == ':' && colonPasswordStart == NULL) {
colonPasswordStart = p;
} else if (*p == '@') {
// We found <username> (and perhaps <password>). Copy them into newly-allocated result strings:
if (colonPasswordStart == NULL) colonPasswordStart = p;
char const* usernameStart = from;
unsigned usernameLen = colonPasswordStart - usernameStart;
username = new char[usernameLen + 1] ; // allow for the trailing '\0'
copyUsernameOrPasswordStringFromURL(username, usernameStart, usernameLen);
char const* passwordStart = colonPasswordStart;
if (passwordStart < p) ++passwordStart; // skip over the ':'
unsigned passwordLen = p - passwordStart;
password = new char[passwordLen + 1]; // allow for the trailing '\0'
copyUsernameOrPasswordStringFromURL(password, passwordStart, passwordLen);
from = p + 1; // skip over the '@'
break;
}
}
// Next, parse <server-address-or-name>
char* to = &parseBuffer[0];
unsigned i;
live_ip_ver = LIVE_IP_VER_4; //默認爲IPv4
if (*from == '[') //如果地址是以符號[開頭,則爲IPv6 因爲ipv6的地址是以符號[開頭
{
live_ip_ver = LIVE_IP_VER_6;
}
if (live_ip_ver == LIVE_IP_VER_6)
{
*from ++; // 跳過符號[
for (i = 0; i < parseBufferSize; ++i) {
if (*from == '\0' || *from == ']' || *from == '/') {
// We've completed parsing the address
*to = '\0';
break;
}
*to++ = *from++;
}
if (i == parseBufferSize) {
env.setResultMsg("URL is too long");
break;
}
*from ++; // 跳過符號]
}
else //IPV4
{
for (i = 0; i < parseBufferSize; ++i) {
if (*from == '\0' || *from == ':' || *from == '/') {
// We've completed parsing the address
*to = '\0';
break;
}
*to++ = *from++;
}
if (i == parseBufferSize) {
env.setResultMsg("URL is too long");
break;
}
}
//rtsp://[2001:0:9d38:953c:14b3:7a:3f57:fe40]:554/ch1
//strcpy(parseBuffer, "2001:0:9d38:953c:38b0:d177:88d8:a5e0");
NetAddressList addresses(parseBuffer);
if (addresses.numAddresses() == 0) {
env.setResultMsg("Failed to find network address for \"",
parseBuffer, "\"");
break;
}
address = *(addresses.firstAddress());
portNum = 554; // default value
char nextChar = *from;
if (nextChar == ':') {
int portNumInt;
if (sscanf(++from, "%d", &portNumInt) != 1) {
env.setResultMsg("No port number follows ':'");
break;
}
if (portNumInt < 1 || portNumInt > 65535) {
env.setResultMsg("Bad port number");
break;
}
portNum = (portNumBits)portNumInt;
while (*from >= '0' && *from <= '9') ++from; // skip over port number
}
// The remainder of the URL is the suffix:
if (urlSuffix != NULL) *urlSuffix = from;
return True;
} while (0);
return False;
}
其中, live_ip_ver 爲全局變量,用於標識該IP地址類型;
後面用到struct sockaddr_in 和 struct in_addr 的地方, 使用LIVE_NET_ADDRESS_SOCKADDR_IN來區分,並進行相應的處理;
live555中,就不能使用live_ip_ver這個全局變量了, 因爲要同時兼容IPv4和IPv6, 將在下篇說明;
重要性
live555的ipv6技術雖然是很小的一個點,但是在越來越物聯網的現在,無論是上架AppStore還是投標競標,ipv6都將成爲一個關鍵的技術點;