network: ip
libmill是一个基于c语言开发的go风格协程库，实现了go风格的协程操作、chan操作、非阻塞的网络io操作等等，是一个不错的linux平台下c风格协程库实现。如果你想从0到1的快速了解如何开发一个协程库，libmill将是一个非常不错的案例；如果你想更深入地了解go，libmill里面也借鉴了go的一些设计思想；或者你想在生产环境中使用，开发者也提供了一个更健壮的版本libdill。
file: ip.h
int mill_ipfamily(ipaddr addr);
int mill_iplen(ipaddr addr);
int mill_ipport(ipaddr addr);file: ip.c
MILL_CT_ASSERT(sizeof(ipaddr) >= sizeof(struct sockaddr_in));
MILL_CT_ASSERT(sizeof(ipaddr) >= sizeof(struct sockaddr_in6));
static struct dns_resolv_conf *mill_dns_conf = NULL;
static struct dns_hosts *mill_dns_hosts = NULL;
static struct dns_hints *mill_dns_hints = NULL;
// 创建一个ip地址为INADDR_ANY、指定端口port、mode=ipv4/ipv6的ip地址
static ipaddr mill_ipany(int port, int mode)
{
ipaddr addr;
if(mill_slow(port < 0 || port > 0xffff)) {
((struct sockaddr*)&addr)->sa_family = AF_UNSPEC;
errno = EINVAL;
return addr;
}
if (mode == 0 || mode == IPADDR_IPV4 || mode == IPADDR_PREF_IPV4) {
struct sockaddr_in *ipv4 = (struct sockaddr_in*)&addr;
ipv4->sin_family = AF_INET;
ipv4->sin_addr.s_addr = htonl(INADDR_ANY);
ipv4->sin_port = htons((uint16_t)port);
}
else {
struct sockaddr_in6 *ipv6 = (struct sockaddr_in6*)&addr;
ipv6->sin6_family = AF_INET6;
memcpy(&ipv6->sin6_addr, &in6addr_any, sizeof(in6addr_any));
ipv6->sin6_port = htons((uint16_t)port);
}
errno = 0;
return addr;
}
// 将点分十进制ipv4地址:端口号=ip:port转换为二进制格式（已转为字节序）
static ipaddr mill_ipv4_literal(const char *addr, int port) {
ipaddr raddr;
struct sockaddr_in *ipv4 = (struct sockaddr_in*)&raddr;
int rc = inet_pton(AF_INET, addr, &ipv4->sin_addr);
mill_assert(rc >= 0);
if(rc == 1) {
ipv4->sin_family = AF_INET;
ipv4->sin_port = htons((uint16_t)port);
errno = 0;
return raddr;
}
ipv4->sin_family = AF_UNSPEC;
errno = EINVAL;
return raddr;
}
// 将点分ipv4地址:端口号=ipv6:port转换为二进制格式（已转网络字节序）
static ipaddr mill_ipv6_literal(const char *addr, int port) {
ipaddr raddr;
struct sockaddr_in6 *ipv6 = (struct sockaddr_in6*)&raddr;
int rc = inet_pton(AF_INET6, addr, &ipv6->sin6_addr);
mill_assert(rc >= 0);
if(rc == 1) {
ipv6->sin6_family = AF_INET6;
ipv6->sin6_port = htons((uint16_t)port);
errno = 0;
return raddr;
}
ipv6->sin6_family = AF_UNSPEC;
errno = EINVAL;
return raddr;
}
// 转换ipv4地址或者ipv6地址为二进制地址格式（组合调用上面的函数mill_ipv4/6_literal）
static ipaddr mill_ipliteral(const char *addr, int port, int mode) {
ipaddr raddr;
struct sockaddr *sa = (struct sockaddr*)&raddr;
if(mill_slow(!addr || port < 0 || port > 0xffff)) {
sa->sa_family = AF_UNSPEC;
errno = EINVAL;
return raddr;
}
switch(mode) {
case IPADDR_IPV4:
return mill_ipv4_literal(addr, port);
case IPADDR_IPV6:
return mill_ipv6_literal(addr, port);
case 0:
case IPADDR_PREF_IPV4:
raddr = mill_ipv4_literal(addr, port);
if(errno == 0)
return raddr;
return mill_ipv6_literal(addr, port);
case IPADDR_PREF_IPV6:
raddr = mill_ipv6_literal(addr, port);
if(errno == 0)
return raddr;
return mill_ipv4_literal(addr, port);
default:
mill_assert(0);
}
}
// 返回ip地址的地址族
int mill_ipfamily(ipaddr addr) {
return ((struct sockaddr*)&addr)->sa_family;
}
// 返回ip地址结构体长度
int mill_iplen(ipaddr addr) {
return mill_ipfamily(addr) == AF_INET ?
sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6);
}
// 返回ip地址端口号
int mill_ipport(ipaddr addr) {
return ntohs(mill_ipfamily(addr) == AF_INET ?
((struct sockaddr_in*)&addr)->sin_port : ((struct sockaddr_in6*)&addr)->sin6_port);
}
// 转换二进制格式的ip地址为点分ipv4或者ipv6地址格式
const char *mill_ipaddrstr_(ipaddr addr, char *ipstr) {
if (mill_ipfamily(addr) == AF_INET) {
return inet_ntop(AF_INET, &(((struct sockaddr_in*)&addr)->sin_addr),
ipstr, INET_ADDRSTRLEN);
}
else {
return inet_ntop(AF_INET6, &(((struct sockaddr_in6*)&addr)->sin6_addr),
ipstr, INET6_ADDRSTRLEN);
}
}
// 获取本地ip地址
// 二进制格式地址，name可以为空、可以为ipv4或ipv6点分表示形式、可以为接口名称
ipaddr mill_iplocal_(const char *name, int port, int mode) {
if(!name)
return mill_ipany(port, mode);
ipaddr addr = mill_ipliteral(name, port, mode);
#if defined __sun
return addr;
#else
if(errno == 0)
return addr;
/* Address is not a literal. It must be an interface name then. */
struct ifaddrs *ifaces = NULL;
int rc = getifaddrs (&ifaces);
mill_assert (rc == 0);
mill_assert (ifaces);
/* Find first IPv4 and first IPv6 address. */
struct ifaddrs *ipv4 = NULL;
struct ifaddrs *ipv6 = NULL;
struct ifaddrs *it;
for(it = ifaces; it != NULL; it = it->ifa_next) {
if(!it->ifa_addr)
continue;
if(strcmp(it->ifa_name, name) != 0)
continue;
switch(it->ifa_addr->sa_family) {
case AF_INET:
mill_assert(!ipv4);
ipv4 = it;
break;
case AF_INET6:
mill_assert(!ipv6);
ipv6 = it;
break;
}
if(ipv4 && ipv6)
break;
}
/* Choose the correct address family based on mode. */
switch(mode) {
case IPADDR_IPV4:
ipv6 = NULL;
break;
case IPADDR_IPV6:
ipv4 = NULL;
break;
case 0:
case IPADDR_PREF_IPV4:
if(ipv4)
ipv6 = NULL;
break;
case IPADDR_PREF_IPV6:
if(ipv6)
ipv4 = NULL;
break;
default:
mill_assert(0);
}
if(ipv4) {
struct sockaddr_in *inaddr = (struct sockaddr_in*)&addr;
memcpy(inaddr, ipv4->ifa_addr, sizeof (struct sockaddr_in));
inaddr->sin_port = htons(port);
freeifaddrs(ifaces);
errno = 0;
return addr;
}
if(ipv6) {
struct sockaddr_in6 *inaddr = (struct sockaddr_in6*)&addr;
memcpy(inaddr, ipv6->ifa_addr, sizeof (struct sockaddr_in6));
inaddr->sin6_port = htons(port);
freeifaddrs(ifaces);
errno = 0;
return addr;
}
freeifaddrs(ifaces);
((struct sockaddr*)&addr)->sa_family = AF_UNSPEC;
errno = ENODEV;
return addr;
#endif
}
// 获取远程机器ip地址的二进制格式
// name可以是ipv4或ipv6点分表示形式、域名domain（这里要用到dns查询）
ipaddr mill_ipremote_(const char *name, int port, int mode, int64_t deadline) {
int rc;
ipaddr addr = mill_ipliteral(name, port, mode);
if(errno == 0)
return addr;
/* Load DNS config files, unless they are already chached. */
if(mill_slow(!mill_dns_conf)) {
/* TODO: Maybe re-read the configuration once in a while? */
mill_dns_conf = dns_resconf_local(&rc);
mill_assert(mill_dns_conf);
mill_dns_hosts = dns_hosts_local(&rc);
mill_assert(mill_dns_hosts);
mill_dns_hints = dns_hints_local(mill_dns_conf, &rc);
mill_assert(mill_dns_hints);
}
/* Let's do asynchronous DNS query here. */
struct dns_resolver *resolver = dns_res_open(mill_dns_conf, mill_dns_hosts,
mill_dns_hints, NULL, dns_opts(), &rc);
mill_assert(resolver);
mill_assert(port >= 0 && port <= 0xffff);
char portstr[8];
snprintf(portstr, sizeof(portstr), "%d", port);
struct addrinfo hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
struct dns_addrinfo *ai = dns_ai_open(name, portstr, DNS_T_A, &hints,
resolver, &rc);
mill_assert(ai);
dns_res_close(resolver);
struct addrinfo *ipv4 = NULL;
struct addrinfo *ipv6 = NULL;
struct addrinfo *it = NULL;
while(1) {
rc = dns_ai_nextent(&it, ai);
if(rc == EAGAIN) {
int fd = dns_ai_pollfd(ai);
mill_assert(fd >= 0);
int events = fdwait(fd, FDW_IN, deadline);
/* There's no guarantee that the file descriptor will be reused
in next iteration. We have to clean the fdwait cache here
to be on the safe side. */
fdclean(fd);
if(mill_slow(!events)) {
errno = ETIMEDOUT;
return addr;
}
mill_assert(events == FDW_IN);
continue;
}
if(rc == ENOENT)
break;
if(!ipv4 && it && it->ai_family == AF_INET) {
ipv4 = it;
}
else if(!ipv6 && it && it->ai_family == AF_INET6) {
ipv6 = it;
}
else {
free(it);
}
if(ipv4 && ipv6)
break;
}
switch(mode) {
case IPADDR_IPV4:
if(ipv6) {
free(ipv6);
ipv6 = NULL;
}
break;
case IPADDR_IPV6:
if(ipv4) {
free(ipv4);
ipv4 = NULL;
}
break;
case 0:
case IPADDR_PREF_IPV4:
if(ipv4 && ipv6) {
free(ipv6);
ipv6 = NULL;
}
break;
case IPADDR_PREF_IPV6:
if(ipv6 && ipv4) {
free(ipv4);
ipv4 = NULL;
}
break;
default:
mill_assert(0);
}
if(ipv4) {
struct sockaddr_in *inaddr = (struct sockaddr_in*)&addr;
memcpy(inaddr, ipv4->ai_addr, sizeof (struct sockaddr_in));
inaddr->sin_port = htons(port);
dns_ai_close(ai);
free(ipv4);
errno = 0;
return addr;
}
if(ipv6) {
struct sockaddr_in6 *inaddr = (struct sockaddr_in6*)&addr;
memcpy(inaddr, ipv6->ai_addr, sizeof (struct sockaddr_in6));
inaddr->sin6_port = htons(port);
dns_ai_close(ai);
free(ipv6);
errno = 0;
return addr;
}
dns_ai_close(ai);
((struct sockaddr*)&addr)->sa_family = AF_UNSPEC;
errno = EADDRNOTAVAIL;
return addr;
}Last updated