Skip to content

fix(linux): handle sparse interface indexes and zero MAC addresses #36

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
tobyrschwartz wants to merge 1 commit into from
Closed

fix(linux): handle sparse interface indexes and zero MAC addresses #36

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
44 changes: 20 additions & 24 deletions libxbot-service/src/portable/linux/system.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
//

#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <stdio.h>
#include <sys/ioctl.h>
Expand Down Expand Up @@ -38,40 +39,35 @@ void generateUniqueId() {
return;
}

for (int iface_index = 1;; iface_index++) {
ifreq ifr{};
ifr.ifr_ifindex = iface_index;
struct if_nameindex* interfaces = if_nameindex();
if (!interfaces) {
perror("if_nameindex");
close(fd);
return;
}

// The end
if (ioctl(fd, SIOCGIFNAME, &ifr) < 0) {
break;
}
for (auto* iface = interfaces; iface->if_index != 0; ++iface) {
ifreq ifr{};
strncpy(ifr.ifr_name, iface->if_name, IFNAMSIZ - 1);

// Skip loopback and virtual interfaces by checking interface name prefixes
// This list was suggested by ChatGPT, not sure if it's complete, but it
// looks good to me.
if (strncmp(ifr.ifr_name, "lo", 2) == 0 || strncmp(ifr.ifr_name, "docker", 6) == 0 ||
strncmp(ifr.ifr_name, "veth", 4) == 0 || strncmp(ifr.ifr_name, "virbr", 5) == 0 ||
strncmp(ifr.ifr_name, "br-", 3) == 0 || strncmp(ifr.ifr_name, "wg", 2) == 0 ||
strncmp(ifr.ifr_name, "tun", 3) == 0 || strncmp(ifr.ifr_name, "tap", 3) == 0) {
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0 ||
ifr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
continue;
}

// Get MAC address
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
perror("SIOCGIFHWADDR");
break;
bool nonzero = false;
for (int i = 0; i < 6; ++i) {
nonzero |= (ifr.ifr_hwaddr.sa_data[i] != 0);
}
if (!nonzero) {
continue;
}

node_id_[0] = ifr.ifr_hwaddr.sa_data[0];
node_id_[1] = ifr.ifr_hwaddr.sa_data[1];
node_id_[2] = ifr.ifr_hwaddr.sa_data[2];
node_id_[3] = ifr.ifr_hwaddr.sa_data[3];
node_id_[4] = ifr.ifr_hwaddr.sa_data[4];
node_id_[5] = ifr.ifr_hwaddr.sa_data[5];
memcpy(node_id_, ifr.ifr_hwaddr.sa_data, 6);
break;
}

if_freenameindex(interfaces);
close(fd);
}

Expand Down