live555对ipv6的扩展
从live555的官网看live555的发展历史，实在是历史悠久，保守估计已经发展了至少16年以上了，同时，这也导致了live555在很多架构和考虑上面不能满足现代化的多线程、ipv6方面的需求，虽然官方也开启了对ipv6功能支持的众筹，但是已经很久了，预计很长时间内是不会有这个计划支持了，因为要改动的地方还真是蛮多的：
，在上一期中我们已经为live555的多线程开了个头《经过两个多月的攻关，终于搞定了live555多线程并稳定压测通过》，今天我们要来聊一下我们在live555扩展IPv6方面是怎么做到的！
设计过程
IPV4 地址
rtsp://192.168.1.100:554/ch1
rtsp://admin:12345@192.168.1.100:554/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修改步骤
增加live_ipv4_ipv6.h和live_ipv4_ipv6.cpp两个文件
用途: 在live所有用到类型为netAddressBits的文件中,包含该头文件,针对ipv4和ipv6进行不同的处理;
live_ipv4_ipv6.h
#ifndef __LIVE_IPV4_IPV6
#define __LIVE_IPV4_IPV6
typedef 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
增加以下定义, 并注释掉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; //注释掉该句,在所有用到netAddressBits的地方，均用LIVE_NET_ADDRESS_INADDR替代;
//增加以下定义
typedef struct __LIVE_NET_ADDRESS_SOCKADDR_IN
{
struct sockaddr_in saddr4;
struct sockaddr_in6 saddr6;
}LIVE_NET_ADDRESS_SOCKADDR_IN;
将所有struct in_addr 改为 LIVE_NET_ADDRESS, 除了以下几处:
void AddressString::init(struct in_addr addr)
将所有struct sockaddr_in 改为 LIVE_NET_ADDRESS_SOCKADDR_IN;
在EasyRtspClient中，将调用到LIVE_NET_ADDRESS_SOCKADDR_IN的函数，增加一个参数,用于标识是IPv4还是IPv6;
从调用以下代码开始，进行区分，用于标识该客户端需要使用IPv4还是IPv6进行连接;
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;
//此处检查字符[
for (p = from; *p != ' ' && *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 ' '
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 ' '
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; //默认为IPv4
if (*from == '[') //如果地址是以符号[开头，则为IPv6 因为ipv6的地址是以符号[开头
{
live_ip_ver = LIVE_IP_VER_6;
}
if (live_ip_ver == LIVE_IP_VER_6)
{
*from ++; // 跳过符号[
for (i = 0; i < parseBufferSize; ++i) {
if (*from == ' ' || *from == ']' || *from == '/') {
// We've completed parsing the address
*to = ' ';
break;
}
*to++ = *from++;
}
if (i == parseBufferSize) {
env.setResultMsg("URL is too long");
break;
}
*from ++; // 跳过符号]
}
else //IPV4
{
for (i = 0; i < parseBufferSize; ++i) {
if (*from == ' ' || *from == ':' || *from == '/') {
// We've completed parsing the address
*to = ' ';
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 为全局变量，用于标识该IP地址类型;
后面用到struct sockaddr_in 和 struct in_addr 的地方， 使用LIVE_NET_ADDRESS_SOCKADDR_IN来区分，并进行相应的处理;
live555中，就不能使用live_ip_ver这个全局变量了, 因为要同时兼容IPv4和IPv6, 将在下篇说明；
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