L2TP_ATTR_UDP_CSUM is read by the kernel as a NLA_FLAG value, but is validated as a NLA_U8, so we will write it as an u8, but the value isn't actually being read by the kernel.
It is written by the kernel as a NLA_U8, so we will read as such. Signed-off-by: Asbjørn Sloth Tønnesen <asbj...@asbjorn.st> --- ip/ipl2tp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/ip/ipl2tp.c b/ip/ipl2tp.c index a7cbd66..03ca0cc 100644 --- a/ip/ipl2tp.c +++ b/ip/ipl2tp.c @@ -120,7 +120,7 @@ static int create_tunnel(struct l2tp_parm *p) addattr16(&req.n, 1024, L2TP_ATTR_UDP_SPORT, p->local_udp_port); addattr16(&req.n, 1024, L2TP_ATTR_UDP_DPORT, p->peer_udp_port); if (p->udp_csum) - addattr(&req.n, 1024, L2TP_ATTR_UDP_CSUM); + addattr8(&req.n, 1024, L2TP_ATTR_UDP_CSUM, 1); if (!p->udp6_csum_tx) addattr(&req.n, 1024, L2TP_ATTR_UDP_ZERO_CSUM6_TX); if (!p->udp6_csum_rx) @@ -289,7 +289,9 @@ static int get_response(struct nlmsghdr *n, void *arg) if (attrs[L2TP_ATTR_L2SPEC_LEN]) p->l2spec_len = rta_getattr_u8(attrs[L2TP_ATTR_L2SPEC_LEN]); - p->udp_csum = !!attrs[L2TP_ATTR_UDP_CSUM]; + if (attrs[L2TP_ATTR_UDP_CSUM]) + p->udp_csum = !!rta_getattr_u8(attrs[L2TP_ATTR_UDP_CSUM]); + /* * Not fetching from L2TP_ATTR_UDP_ZERO_CSUM6_{T,R}X because the * kernel doesn't send it so just leave it as default value. -- 2.10.2