diff options
| -rw-r--r-- | src/network/networkd-link.c | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c index e4800a10de..bc363f95b0 100644 --- a/src/network/networkd-link.c +++ b/src/network/networkd-link.c @@ -1237,12 +1237,38 @@ static int link_enter_join_netdev(Link *link) { static int link_set_ipv4_forward(Link *link) { const char *p = NULL; + bool b; int r; + b = link_ipv4_forward_enabled(link); + p = strappenda("/proc/sys/net/ipv4/conf/", link->ifname, "/forwarding"); - r = write_string_file_no_create(p, one_zero(link_ipv4_forward_enabled(link))); + r = write_string_file_no_create(p, one_zero(b)); if (r < 0) - log_link_warning_errno(link, r, "Cannot configure IPv4 forwarding for interface: %m"); + log_link_warning_errno(link, r, "Cannot configure IPv4 forwarding for interface %s: %m", link->ifname); + + if (b) { + _cleanup_free_ char *buf = NULL; + + /* If IP forwarding is turned on for this interface, + * then propagate this to the global setting. Given + * that turning this on has side-effects on other + * fields, we'll try to avoid doing this unless + * necessary, hence check the previous value + * first. Note that we never turn this option off + * again, since all interfaces we manage do not do + * forwarding anyway by default, and ownership rules + * of this control are so unclear. */ + + r = read_one_line_file("/proc/sys/net/ipv4/ip_forward", &buf); + if (r < 0) + log_link_warning_errno(link, r, "Cannot read /proc/sys/net/ipv4/ip_forward: %m"); + else if (!streq(buf, "1")) { + r = write_string_file_no_create("/proc/sys/net/ipv4/ip_forward", "1"); + if (r < 0) + log_link_warning_errno(link, r, "Cannot write /proc/sys/net/ipv4/ip_forward: %m"); + } + } return 0; } |