| Message ID | 82b358f40c81cfdecbfc394113be40fd1f682043.1601387231.git.lucien.xin@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | sctp: Implement RFC6951: UDP Encapsulation of SCTP | expand |
Hi Xin,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on net-next/master]
url: https://github.com/0day-ci/linux/commits/Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159
base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 280095713ce244e8dbdfb059cdca695baa72230a
config: ia64-randconfig-r014-20200929 (attached as .config)
compiler: ia64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/a1016fd4a55f176fcc2eae05052a61ad7d5a142b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159
git checkout a1016fd4a55f176fcc2eae05052a61ad7d5a142b
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
net/sctp/protocol.c: In function 'sctp_udp_sock_start':
>> net/sctp/protocol.c:894:11: error: 'struct udp_port_cfg' has no member named 'local_ip6'; did you mean 'local_ip'?
894 | udp_conf.local_ip6 = in6addr_any;
| ^~~~~~~~~
| local_ip
vim +894 net/sctp/protocol.c
a330bee1c278f8 Xin Long 2020-09-29 870
140bb5309cf409 Xin Long 2020-09-29 871 int sctp_udp_sock_start(struct net *net)
140bb5309cf409 Xin Long 2020-09-29 872 {
140bb5309cf409 Xin Long 2020-09-29 873 struct udp_tunnel_sock_cfg tuncfg = {NULL};
140bb5309cf409 Xin Long 2020-09-29 874 struct udp_port_cfg udp_conf = {0};
140bb5309cf409 Xin Long 2020-09-29 875 struct socket *sock;
140bb5309cf409 Xin Long 2020-09-29 876 int err;
140bb5309cf409 Xin Long 2020-09-29 877
140bb5309cf409 Xin Long 2020-09-29 878 udp_conf.family = AF_INET;
140bb5309cf409 Xin Long 2020-09-29 879 udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
140bb5309cf409 Xin Long 2020-09-29 880 udp_conf.local_udp_port = htons(net->sctp.udp_port);
140bb5309cf409 Xin Long 2020-09-29 881 err = udp_sock_create(net, &udp_conf, &sock);
140bb5309cf409 Xin Long 2020-09-29 882 if (err)
140bb5309cf409 Xin Long 2020-09-29 883 return err;
140bb5309cf409 Xin Long 2020-09-29 884
140bb5309cf409 Xin Long 2020-09-29 885 tuncfg.encap_type = 1;
140bb5309cf409 Xin Long 2020-09-29 886 tuncfg.encap_rcv = sctp_udp_rcv;
a330bee1c278f8 Xin Long 2020-09-29 887 tuncfg.encap_err_lookup = sctp_udp_err_lookup;
140bb5309cf409 Xin Long 2020-09-29 888 setup_udp_tunnel_sock(net, sock, &tuncfg);
140bb5309cf409 Xin Long 2020-09-29 889 net->sctp.udp4_sock = sock->sk;
140bb5309cf409 Xin Long 2020-09-29 890
cff8956126170d Xin Long 2020-09-29 891 memset(&udp_conf, 0, sizeof(udp_conf));
cff8956126170d Xin Long 2020-09-29 892
cff8956126170d Xin Long 2020-09-29 893 udp_conf.family = AF_INET6;
cff8956126170d Xin Long 2020-09-29 @894 udp_conf.local_ip6 = in6addr_any;
cff8956126170d Xin Long 2020-09-29 895 udp_conf.local_udp_port = htons(net->sctp.udp_port);
cff8956126170d Xin Long 2020-09-29 896 udp_conf.use_udp6_rx_checksums = true;
cff8956126170d Xin Long 2020-09-29 897 udp_conf.ipv6_v6only = true;
cff8956126170d Xin Long 2020-09-29 898 err = udp_sock_create(net, &udp_conf, &sock);
cff8956126170d Xin Long 2020-09-29 899 if (err) {
cff8956126170d Xin Long 2020-09-29 900 udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
cff8956126170d Xin Long 2020-09-29 901 net->sctp.udp4_sock = NULL;
cff8956126170d Xin Long 2020-09-29 902 return err;
cff8956126170d Xin Long 2020-09-29 903 }
cff8956126170d Xin Long 2020-09-29 904
cff8956126170d Xin Long 2020-09-29 905 tuncfg.encap_type = 1;
cff8956126170d Xin Long 2020-09-29 906 tuncfg.encap_rcv = sctp_udp_rcv;
a330bee1c278f8 Xin Long 2020-09-29 907 tuncfg.encap_err_lookup = sctp_udp_err_lookup;
cff8956126170d Xin Long 2020-09-29 908 setup_udp_tunnel_sock(net, sock, &tuncfg);
cff8956126170d Xin Long 2020-09-29 909 net->sctp.udp6_sock = sock->sk;
cff8956126170d Xin Long 2020-09-29 910
140bb5309cf409 Xin Long 2020-09-29 911 return 0;
140bb5309cf409 Xin Long 2020-09-29 912 }
140bb5309cf409 Xin Long 2020-09-29 913
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi Xin,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on net-next/master]
url: https://github.com/0day-ci/linux/commits/Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159
base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 280095713ce244e8dbdfb059cdca695baa72230a
config: x86_64-randconfig-a002-20200929 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project de55ebe3bbc77882901ae2b9654503b7611b28f3)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
# https://github.com/0day-ci/linux/commit/a1016fd4a55f176fcc2eae05052a61ad7d5a142b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159
git checkout a1016fd4a55f176fcc2eae05052a61ad7d5a142b
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> net/sctp/protocol.c:894:11: error: no member named 'local_ip6' in 'struct udp_port_cfg'; did you mean 'local_ip'?
udp_conf.local_ip6 = in6addr_any;
^~~~~~~~~
local_ip
include/net/udp_tunnel.h:18:19: note: 'local_ip' declared here
struct in_addr local_ip;
^
>> net/sctp/protocol.c:894:21: error: assigning to 'struct in_addr' from incompatible type 'const struct in6_addr'
udp_conf.local_ip6 = in6addr_any;
^ ~~~~~~~~~~~
2 errors generated.
vim +894 net/sctp/protocol.c
a330bee1c278f86 Xin Long 2020-09-29 870
140bb5309cf4095 Xin Long 2020-09-29 871 int sctp_udp_sock_start(struct net *net)
140bb5309cf4095 Xin Long 2020-09-29 872 {
140bb5309cf4095 Xin Long 2020-09-29 873 struct udp_tunnel_sock_cfg tuncfg = {NULL};
140bb5309cf4095 Xin Long 2020-09-29 874 struct udp_port_cfg udp_conf = {0};
140bb5309cf4095 Xin Long 2020-09-29 875 struct socket *sock;
140bb5309cf4095 Xin Long 2020-09-29 876 int err;
140bb5309cf4095 Xin Long 2020-09-29 877
140bb5309cf4095 Xin Long 2020-09-29 878 udp_conf.family = AF_INET;
140bb5309cf4095 Xin Long 2020-09-29 879 udp_conf.local_ip.s_addr = htonl(INADDR_ANY);
140bb5309cf4095 Xin Long 2020-09-29 880 udp_conf.local_udp_port = htons(net->sctp.udp_port);
140bb5309cf4095 Xin Long 2020-09-29 881 err = udp_sock_create(net, &udp_conf, &sock);
140bb5309cf4095 Xin Long 2020-09-29 882 if (err)
140bb5309cf4095 Xin Long 2020-09-29 883 return err;
140bb5309cf4095 Xin Long 2020-09-29 884
140bb5309cf4095 Xin Long 2020-09-29 885 tuncfg.encap_type = 1;
140bb5309cf4095 Xin Long 2020-09-29 886 tuncfg.encap_rcv = sctp_udp_rcv;
a330bee1c278f86 Xin Long 2020-09-29 887 tuncfg.encap_err_lookup = sctp_udp_err_lookup;
140bb5309cf4095 Xin Long 2020-09-29 888 setup_udp_tunnel_sock(net, sock, &tuncfg);
140bb5309cf4095 Xin Long 2020-09-29 889 net->sctp.udp4_sock = sock->sk;
140bb5309cf4095 Xin Long 2020-09-29 890
cff8956126170d6 Xin Long 2020-09-29 891 memset(&udp_conf, 0, sizeof(udp_conf));
cff8956126170d6 Xin Long 2020-09-29 892
cff8956126170d6 Xin Long 2020-09-29 893 udp_conf.family = AF_INET6;
cff8956126170d6 Xin Long 2020-09-29 @894 udp_conf.local_ip6 = in6addr_any;
cff8956126170d6 Xin Long 2020-09-29 895 udp_conf.local_udp_port = htons(net->sctp.udp_port);
cff8956126170d6 Xin Long 2020-09-29 896 udp_conf.use_udp6_rx_checksums = true;
cff8956126170d6 Xin Long 2020-09-29 897 udp_conf.ipv6_v6only = true;
cff8956126170d6 Xin Long 2020-09-29 898 err = udp_sock_create(net, &udp_conf, &sock);
cff8956126170d6 Xin Long 2020-09-29 899 if (err) {
cff8956126170d6 Xin Long 2020-09-29 900 udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket);
cff8956126170d6 Xin Long 2020-09-29 901 net->sctp.udp4_sock = NULL;
cff8956126170d6 Xin Long 2020-09-29 902 return err;
cff8956126170d6 Xin Long 2020-09-29 903 }
cff8956126170d6 Xin Long 2020-09-29 904
cff8956126170d6 Xin Long 2020-09-29 905 tuncfg.encap_type = 1;
cff8956126170d6 Xin Long 2020-09-29 906 tuncfg.encap_rcv = sctp_udp_rcv;
a330bee1c278f86 Xin Long 2020-09-29 907 tuncfg.encap_err_lookup = sctp_udp_err_lookup;
cff8956126170d6 Xin Long 2020-09-29 908 setup_udp_tunnel_sock(net, sock, &tuncfg);
cff8956126170d6 Xin Long 2020-09-29 909 net->sctp.udp6_sock = sock->sk;
cff8956126170d6 Xin Long 2020-09-29 910
140bb5309cf4095 Xin Long 2020-09-29 911 return 0;
140bb5309cf4095 Xin Long 2020-09-29 912 }
140bb5309cf4095 Xin Long 2020-09-29 913
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On Wed, Sep 30, 2020 at 12:26 AM kernel test robot <lkp@intel.com> wrote: > > Hi Xin, > > Thank you for the patch! Yet something to improve: > > [auto build test ERROR on net-next/master] > > url: https://github.com/0day-ci/linux/commits/Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159 > base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 280095713ce244e8dbdfb059cdca695baa72230a > config: ia64-randconfig-r014-20200929 (attached as .config) > compiler: ia64-linux-gcc (GCC) 9.3.0 > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://github.com/0day-ci/linux/commit/a1016fd4a55f176fcc2eae05052a61ad7d5a142b > git remote add linux-review https://github.com/0day-ci/linux > git fetch --no-tags linux-review Xin-Long/sctp-Implement-RFC6951-UDP-Encapsulation-of-SCTP/20200929-215159 > git checkout a1016fd4a55f176fcc2eae05052a61ad7d5a142b > # save the attached .config to linux build tree > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@intel.com> > > All errors (new ones prefixed by >>): > > net/sctp/protocol.c: In function 'sctp_udp_sock_start': > >> net/sctp/protocol.c:894:11: error: 'struct udp_port_cfg' has no member named 'local_ip6'; did you mean 'local_ip'? > 894 | udp_conf.local_ip6 = in6addr_any; > | ^~~~~~~~~ > | local_ip > > vim +894 net/sctp/protocol.c > > a330bee1c278f8 Xin Long 2020-09-29 870 > 140bb5309cf409 Xin Long 2020-09-29 871 int sctp_udp_sock_start(struct net *net) > 140bb5309cf409 Xin Long 2020-09-29 872 { > 140bb5309cf409 Xin Long 2020-09-29 873 struct udp_tunnel_sock_cfg tuncfg = {NULL}; > 140bb5309cf409 Xin Long 2020-09-29 874 struct udp_port_cfg udp_conf = {0}; > 140bb5309cf409 Xin Long 2020-09-29 875 struct socket *sock; > 140bb5309cf409 Xin Long 2020-09-29 876 int err; > 140bb5309cf409 Xin Long 2020-09-29 877 > 140bb5309cf409 Xin Long 2020-09-29 878 udp_conf.family = AF_INET; > 140bb5309cf409 Xin Long 2020-09-29 879 udp_conf.local_ip.s_addr = htonl(INADDR_ANY); > 140bb5309cf409 Xin Long 2020-09-29 880 udp_conf.local_udp_port = htons(net->sctp.udp_port); > 140bb5309cf409 Xin Long 2020-09-29 881 err = udp_sock_create(net, &udp_conf, &sock); > 140bb5309cf409 Xin Long 2020-09-29 882 if (err) > 140bb5309cf409 Xin Long 2020-09-29 883 return err; > 140bb5309cf409 Xin Long 2020-09-29 884 > 140bb5309cf409 Xin Long 2020-09-29 885 tuncfg.encap_type = 1; > 140bb5309cf409 Xin Long 2020-09-29 886 tuncfg.encap_rcv = sctp_udp_rcv; > a330bee1c278f8 Xin Long 2020-09-29 887 tuncfg.encap_err_lookup = sctp_udp_err_lookup; > 140bb5309cf409 Xin Long 2020-09-29 888 setup_udp_tunnel_sock(net, sock, &tuncfg); > 140bb5309cf409 Xin Long 2020-09-29 889 net->sctp.udp4_sock = sock->sk; > 140bb5309cf409 Xin Long 2020-09-29 890 > cff8956126170d Xin Long 2020-09-29 891 memset(&udp_conf, 0, sizeof(udp_conf)); > cff8956126170d Xin Long 2020-09-29 892 > cff8956126170d Xin Long 2020-09-29 893 udp_conf.family = AF_INET6; > cff8956126170d Xin Long 2020-09-29 @894 udp_conf.local_ip6 = in6addr_any; > cff8956126170d Xin Long 2020-09-29 895 udp_conf.local_udp_port = htons(net->sctp.udp_port); > cff8956126170d Xin Long 2020-09-29 896 udp_conf.use_udp6_rx_checksums = true; > cff8956126170d Xin Long 2020-09-29 897 udp_conf.ipv6_v6only = true; > cff8956126170d Xin Long 2020-09-29 898 err = udp_sock_create(net, &udp_conf, &sock); > cff8956126170d Xin Long 2020-09-29 899 if (err) { > cff8956126170d Xin Long 2020-09-29 900 udp_tunnel_sock_release(net->sctp.udp4_sock->sk_socket); > cff8956126170d Xin Long 2020-09-29 901 net->sctp.udp4_sock = NULL; > cff8956126170d Xin Long 2020-09-29 902 return err; > cff8956126170d Xin Long 2020-09-29 903 } > cff8956126170d Xin Long 2020-09-29 904 > cff8956126170d Xin Long 2020-09-29 905 tuncfg.encap_type = 1; > cff8956126170d Xin Long 2020-09-29 906 tuncfg.encap_rcv = sctp_udp_rcv; > a330bee1c278f8 Xin Long 2020-09-29 907 tuncfg.encap_err_lookup = sctp_udp_err_lookup; > cff8956126170d Xin Long 2020-09-29 908 setup_udp_tunnel_sock(net, sock, &tuncfg); > cff8956126170d Xin Long 2020-09-29 909 net->sctp.udp6_sock = sock->sk; #if IS_ENABLED(CONFIG_IPV6) is needed for this part. Thanks. > cff8956126170d Xin Long 2020-09-29 910 > 140bb5309cf409 Xin Long 2020-09-29 911 return 0; > 140bb5309cf409 Xin Long 2020-09-29 912 } > 140bb5309cf409 Xin Long 2020-09-29 913 > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/net/sctp/output.c b/net/sctp/output.c index fb16500..6614c9f 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -514,8 +514,8 @@ static int sctp_packet_pack(struct sctp_packet *packet, if (sctp_checksum_disable) return 1; - if (!(skb_dst(head)->dev->features & NETIF_F_SCTP_CRC) || - dst_xfrm(skb_dst(head)) || packet->ipfragok) { + if (!(tp->dst->dev->features & NETIF_F_SCTP_CRC) || + dst_xfrm(tp->dst) || packet->ipfragok || tp->encap_port) { struct sctphdr *sh = (struct sctphdr *)skb_transport_header(head); @@ -542,7 +542,6 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp) struct sctp_association *asoc = tp->asoc; struct sctp_chunk *chunk, *tmp; int pkt_count, gso = 0; - struct dst_entry *dst; struct sk_buff *head; struct sctphdr *sh; struct sock *sk; @@ -579,13 +578,11 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp) sh->checksum = 0; /* drop packet if no dst */ - dst = dst_clone(tp->dst); - if (!dst) { + if (!tp->dst) { IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); kfree_skb(head); goto out; } - skb_dst_set(head, dst); rcu_read_lock(); if (__sk_dst_get(sk) != tp->dst) { diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index c73fd5f..6606a63 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -44,6 +44,7 @@ #include <net/addrconf.h> #include <net/inet_common.h> #include <net/inet_ecn.h> +#include <net/udp_tunnel.h> #define MAX_SCTP_PORT_HASH_ENTRIES (64 * 1024) @@ -1053,25 +1054,46 @@ static int sctp_inet_supported_addrs(const struct sctp_sock *opt, } /* Wrapper routine that calls the ip transmit routine. */ -static inline int sctp_v4_xmit(struct sk_buff *skb, - struct sctp_transport *transport) +static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t) { - struct inet_sock *inet = inet_sk(skb->sk); + struct dst_entry *dst = dst_clone(t->dst); + struct flowi4 *fl4 = &t->fl.u.ip4; + struct sock *sk = skb->sk; + struct inet_sock *inet = inet_sk(sk); + struct net *net = sock_net(sk); __u8 dscp = inet->tos; + __be16 df = 0; pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb, - skb->len, &transport->fl.u.ip4.saddr, - &transport->fl.u.ip4.daddr); + skb->len, &fl4->saddr, &fl4->daddr); + + if (t->dscp & SCTP_DSCP_SET_MASK) + dscp = t->dscp & SCTP_DSCP_VAL_MASK; - if (transport->dscp & SCTP_DSCP_SET_MASK) - dscp = transport->dscp & SCTP_DSCP_VAL_MASK; + inet->pmtudisc = t->param_flags & SPP_PMTUD_ENABLE ? IP_PMTUDISC_DO + : IP_PMTUDISC_DONT; + SCTP_INC_STATS(net, SCTP_MIB_OUTSCTPPACKS); - inet->pmtudisc = transport->param_flags & SPP_PMTUD_ENABLE ? - IP_PMTUDISC_DO : IP_PMTUDISC_DONT; + if (!t->encap_port || !net->sctp.udp_port) { + skb_dst_set(skb, dst); + return __ip_queue_xmit(sk, skb, &t->fl, dscp); + } + + if (skb_is_gso(skb)) + skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; - SCTP_INC_STATS(sock_net(&inet->sk), SCTP_MIB_OUTSCTPPACKS); + if (ip_dont_fragment(sk, dst) && !skb->ignore_df) + df = htons(IP_DF); - return __ip_queue_xmit(&inet->sk, skb, &transport->fl, dscp); + skb->encapsulation = 1; + skb_reset_inner_mac_header(skb); + skb_reset_inner_transport_header(skb); + skb_set_inner_ipproto(skb, IPPROTO_SCTP); + udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr, + fl4->daddr, dscp, ip4_dst_hoplimit(dst), df, + htons(net->sctp.udp_port), htons(t->encap_port), + false, false); + return 0; } static struct sctp_af sctp_af_inet;
This patch does what the rfc6951#section-5.3 says for ipv4: "Within the UDP header, the source port MUST be the local UDP encapsulation port number of the SCTP stack, and the destination port MUST be the remote UDP encapsulation port number maintained for the association and the destination address to which the packet is sent (see Section 5.1). Because the SCTP packet is the UDP payload, the length of the UDP packet MUST be the length of the SCTP packet plus the size of the UDP header. The SCTP checksum MUST be computed for IPv4 and IPv6, and the UDP checksum SHOULD be computed for IPv4 and IPv6." Some places need to be adjusted in sctp_packet_transmit(): 1. For non-gso packets, when transport's encap_port is set, sctp checksum has to be done in sctp_packet_pack(), as the outer udp will use ip_summed = CHECKSUM_PARTIAL to do the offload setting for checksum. 2. Delay calling dst_clone() and skb_dst_set() for non-udp packets until sctp_v4_xmit(), as for udp packets, skb_dst_set() is not needed before calling udp_tunnel_xmit_skb(). then in sctp_v4_xmit(): 1. Go to udp_tunnel_xmit_skb() only when transport->encap_port and net->sctp.udp_port both are set, as these are one for dst port and another for src port. 2. For gso packet, SKB_GSO_UDP_TUNNEL_CSUM is set for gso_type, and with this udp checksum can be done in __skb_udp_tunnel_segment() for each segments after the sctp gso. 3. inner_mac_header and inner_transport_header are set, as these will be needed in __skb_udp_tunnel_segment() to find the right headers. 4. df and ttl are calculated, as these are the required params by udp_tunnel_xmit_skb(). 5. nocheck param has to be false, as "the UDP checksum SHOULD be computed for IPv4 and IPv6", says in rfc6951#section-5.3. Signed-off-by: Xin Long <lucien.xin@gmail.com> --- net/sctp/output.c | 9 +++------ net/sctp/protocol.c | 44 +++++++++++++++++++++++++++++++++----------- 2 files changed, 36 insertions(+), 17 deletions(-)