linux - linux下与wifi接口(interface)绑定(bind)

Question

我正在开发一个基于Linux的系统，该系统具有LAN和WIFI接口(interface)。但我必须仅将我的套接字与 wifi 接口(interface)绑定(bind)。有没有什么通用的方法可以找出哪个接口(interface)是wifi，这样我就可以用它来装我的 socket ？如果没有，我是否可以绑定(bind)并接收来自两个接口(interface)的请求？

目前，我正在使用 INADDR_ANY 进行绑定(bind)。我知道如何与 eth0 等特定接口(interface)绑定(bind)，但我找不到任何方法来确定 eth0 是否是 wifi 接口(interface)；至少在C中。使用INADDR_ANY，我将接收发送到任何接口(interface)的数据包，但我的发送可能会尝试通过LAN接口(interface)发送它；这不是我想要的。

Answer 1

这个片段可以帮助你，它比我想象的更复杂:

if (getifaddrs(&ifaddrs) < 0) {
my_loge(CRIT, "address detection failed");
return(0);
}

// zero
count = 0;

// unset all but CAP_HOST and CAP_ROUTER
sysinfo->cap &= (CAP_HOST|CAP_ROUTER);
sysinfo->cap_active &= (CAP_HOST|CAP_ROUTER);
// reset counter
sysinfo->physif_count = 0;

// mark all interfaces
TAILQ_FOREACH(netif, netifs, entries) {
netif->type = NETIF_OLD;
}

for (ifaddr = ifaddrs; ifaddr != NULL; ifaddr = ifaddr->ifa_next) {

// skip interfaces without addresses
if (ifaddr->ifa_addr == NULL) {
    my_log(INFO, "skipping interface %s", ifaddr->ifa_name);
    continue;
}

// only handle datalink addresses
if (ifaddr->ifa_addr->sa_family != NETIF_AF)
    continue;

// prepare ifr struct
memset(&ifr, 0, sizeof(ifr));
strlcpy(ifr.ifr_name, ifaddr->ifa_name, sizeof(ifr.ifr_name));


// skip non-ethernet interfaces
memcpy(&saddrll, ifaddr->ifa_addr, sizeof(saddrll));
if (saddrll.sll_hatype != ARPHRD_ETHER) {
    my_log(INFO, "skipping interface %s", ifaddr->ifa_name);
    continue;
}
index = saddrll.sll_ifindex;
memcpy(&saddrdl, ifaddr->ifa_addr, sizeof(saddrdl));
if ((saddrdl.sdl_type != IFT_BRIDGE) &&
    (saddrdl.sdl_type != IFT_ETHER)) {
if (saddrdl.sdl_type != IFT_ETHER) {
    my_log(INFO, "skipping interface %s", ifaddr->ifa_name);
    continue;
}
index = saddrdl.sdl_index;

// check for interfaces that are down
enabled = 0;
if (ioctl(sockfd, SIOCGIFFLAGS, (caddr_t)&ifr) >= 0)
    enabled = (ifr.ifr_flags & IFF_UP);

// detect interface type
type = netif_type(sockfd, index, ifaddr, &ifr);

if (type == NETIF_REGULAR) { 
    my_log(INFO, "found ethernet interface %s", ifaddr->ifa_name);
    sysinfo->physif_count++;
} else if (type == NETIF_WIRELESS) {
    my_log(INFO, "found wireless interface %s", ifaddr->ifa_name);
    sysinfo->cap |= CAP_WLAN;
    sysinfo->cap_active |= (enabled == 1) ? CAP_WLAN : 0;
} else if (type == NETIF_TAP) {
    my_log(INFO, "found tun/tap interface %s", ifaddr->ifa_name);
} else if (type == NETIF_BONDING) {
    my_log(INFO, "found bond interface %s", ifaddr->ifa_name);
} else if (type == NETIF_BRIDGE) {
    my_log(INFO, "found bridge interface %s", ifaddr->ifa_name);
    sysinfo->cap |= CAP_BRIDGE; 
    sysinfo->cap_active |= (enabled == 1) ? CAP_BRIDGE : 0;
} else if (type == NETIF_VLAN) {
    my_log(INFO, "found vlan interface %s", ifaddr->ifa_name);
} else if (type == NETIF_INVALID) {
    my_log(INFO, "skipping interface %s", ifaddr->ifa_name);
    continue;
}

完整文件位于此处: here