[PATCH v4] ipvs: allow tunneling with gue encapsulation

Jacky Hu
2019-03-17T15:52:12Z

ipip packets are blocked in some public cloud environments, this patch
allows gue encapsulation with the tunneling method, which would make
tunneling working in those environments.

Signed-off-by: Jacky Hu <hengqing.hu@gmail.com>
---
include/net/ip_vs.h | 5 ++
include/uapi/linux/ip_vs.h | 11 +++
net/netfilter/ipvs/ip_vs_ctl.c | 43 ++++++++++-
net/netfilter/ipvs/ip_vs_xmit.c | 124 ++++++++++++++++++++++++++++++--
4 files changed, 178 insertions(+), 5 deletions(-)

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index a0d2e0bb9a94..56c1770b00fe 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -603,6 +603,9 @@ struct ip_vs_dest_user_kern {

/* Address family of addr */
u16 af;
+
+ u16 tun_type; /* tunnel type */
+ __be16 tun_port; /* tunnel port */
};

@@ -663,6 +666,8 @@ struct ip_vs_dest {
atomic_t conn_flags; /* flags to copy to conn */
atomic_t weight; /* server weight */
atomic_t last_weight; /* server latest weight */
+ atomic_t tun_type; /* tunnel type */
+ atomic_t tun_port; /* tunnel port */

refcount_t refcnt; /* reference counter */
struct ip_vs_stats stats; /* statistics */
diff --git a/include/uapi/linux/ip_vs.h b/include/uapi/linux/ip_vs.h
index 1c916b2f89dc..e34f436fc79d 100644
--- a/include/uapi/linux/ip_vs.h
+++ b/include/uapi/linux/ip_vs.h
@@ -124,6 +124,13 @@

#define IP_VS_PEDATA_MAXLEN 255

+/* Tunnel types */
+enum {
+ IP_VS_CONN_F_TUNNEL_TYPE_IPIP = 0, /* IPIP */
+ IP_VS_CONN_F_TUNNEL_TYPE_GUE, /* GUE */
+ IP_VS_CONN_F_TUNNEL_TYPE_MAX,
+};
+
/*
* The struct ip_vs_service_user and struct ip_vs_dest_user are
* used to set IPVS rules through setsockopt.
@@ -392,6 +399,10 @@ enum {

IPVS_DEST_ATTR_STATS64, /* nested attribute for dest stats */

+ IPVS_DEST_ATTR_TUN_TYPE, /* tunnel type */
+
+ IPVS_DEST_ATTR_TUN_PORT, /* tunnel port */
+
__IPVS_DEST_ATTR_MAX,
};

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 432141f04af3..94de9f23013e 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -830,6 +830,10 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
conn_flags = udest->conn_flags & IP_VS_CONN_F_DEST_MASK;
conn_flags |= IP_VS_CONN_F_INACTIVE;

+ /* set the tunnel info */
+ atomic_set(&dest->tun_type, udest->tun_type);
+ atomic_set(&dest->tun_port, udest->tun_port);
+
/* set the IP_VS_CONN_F_NOOUTPUT flag if not masquerading/NAT */
if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != IP_VS_CONN_F_MASQ) {
conn_flags |= IP_VS_CONN_F_NOOUTPUT;
@@ -980,6 +984,17 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
return -ERANGE;
}

+ switch (udest->tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ if (udest->tun_port == 0) {
+ pr_err("%s(): tunnel port is zero\n", __func__);
+ return -EINVAL;
+ }
+ break;
+ default:
+ break;
+ }
+
ip_vs_addr_copy(udest->af, &daddr, &udest->addr);

/* We use function that requires RCU lock */
@@ -1044,6 +1059,17 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
return -ERANGE;
}

+ switch (udest->tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ if (udest->tun_port == 0) {
+ pr_err("%s(): tunnel port is zero\n", __func__);
+ return -EINVAL;
+ }
+ break;
+ default:
+ break;
+ }
+
ip_vs_addr_copy(udest->af, &daddr, &udest->addr);

/* We use function that requires RCU lock */
@@ -2310,6 +2336,7 @@ static void ip_vs_copy_udest_compat(struct ip_vs_dest_user_kern *udest,
udest->u_threshold = udest_compat->u_threshold;
udest->l_threshold = udest_compat->l_threshold;
udest->af = AF_INET;
+ udest->tun_type = IP_VS_CONN_F_TUNNEL_TYPE_IPIP;
}

static int
@@ -2869,6 +2896,8 @@ static const struct nla_policy ip_vs_dest_policy[IPVS_DEST_ATTR_MAX + 1] = {
[IPVS_DEST_ATTR_PERSIST_CONNS] = { .type = NLA_U32 },
[IPVS_DEST_ATTR_STATS] = { .type = NLA_NESTED },
[IPVS_DEST_ATTR_ADDR_FAMILY] = { .type = NLA_U16 },
+ [IPVS_DEST_ATTR_TUN_TYPE] = { .type = NLA_U8 },
+ [IPVS_DEST_ATTR_TUN_PORT] = { .type = NLA_U16 },
};

static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
@@ -3172,6 +3201,10 @@ static int ip_vs_genl_fill_dest(struct sk_buff *skb, struct ip_vs_dest *dest)
IP_VS_CONN_F_FWD_MASK)) ||
nla_put_u32(skb, IPVS_DEST_ATTR_WEIGHT,
atomic_read(&dest->weight)) ||
+ nla_put_u8(skb, IPVS_DEST_ATTR_TUN_TYPE,
+ atomic_read(&dest->tun_type)) ||
+ nla_put_be16(skb, IPVS_DEST_ATTR_TUN_PORT,
+ atomic_read(&dest->tun_port)) ||
nla_put_u32(skb, IPVS_DEST_ATTR_U_THRESH, dest->u_threshold) ||
nla_put_u32(skb, IPVS_DEST_ATTR_L_THRESH, dest->l_threshold) ||
nla_put_u32(skb, IPVS_DEST_ATTR_ACTIVE_CONNS,
@@ -3294,12 +3327,14 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
/* If a full entry was requested, check for the additional fields */
if (full_entry) {
struct nlattr *nla_fwd, *nla_weight, *nla_u_thresh,
- *nla_l_thresh;
+ *nla_l_thresh, *nla_tun_type, *nla_tun_port;

nla_fwd = attrs[IPVS_DEST_ATTR_FWD_METHOD];
nla_weight = attrs[IPVS_DEST_ATTR_WEIGHT];
nla_u_thresh = attrs[IPVS_DEST_ATTR_U_THRESH];
nla_l_thresh = attrs[IPVS_DEST_ATTR_L_THRESH];
+ nla_tun_type = attrs[IPVS_DEST_ATTR_TUN_TYPE];
+ nla_tun_port = attrs[IPVS_DEST_ATTR_TUN_PORT];

if (!(nla_fwd && nla_weight && nla_u_thresh && nla_l_thresh))
return -EINVAL;
@@ -3309,6 +3344,12 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
udest->weight = nla_get_u32(nla_weight);
udest->u_threshold = nla_get_u32(nla_u_thresh);
udest->l_threshold = nla_get_u32(nla_l_thresh);
+
+ if (nla_tun_type)
+ udest->tun_type = nla_get_u8(nla_tun_type);
+
+ if (nla_tun_port)
+ udest->tun_port = nla_get_be16(nla_tun_port);
}

return 0;
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 473cce2a5231..1d02a7ad5c12 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -32,6 +32,7 @@
#include <linux/slab.h>
#include <linux/tcp.h> /* for tcphdr */
#include <net/ip.h>
+#include <net/gue.h>
#include <net/tcp.h> /* for csum_tcpudp_magic */
#include <net/udp.h>
#include <net/icmp.h> /* for icmp_send */
@@ -382,6 +383,15 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
mtu = dst_mtu(&rt->dst);
} else {
mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
+ if (!dest)
+ goto err_put;
+ switch (atomic_read(&dest->tun_type)) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
+ break;
+ default:
+ break;
+ }
if (mtu < 68) {
IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
goto err_put;
@@ -533,6 +543,15 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
mtu = dst_mtu(&rt->dst);
else {
mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
+ if (!dest)
+ goto err_put;
+ switch (atomic_read(&dest->tun_type)) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
+ break;
+ default:
+ break;
+ }
if (mtu < IPV6_MIN_MTU) {
IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
IPV6_MIN_MTU);
@@ -989,6 +1008,41 @@ static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
}
}

+static int
+ipvs_gue_encap(struct net *net, struct sk_buff *skb,
+ struct ip_vs_conn *cp, __u8 *next_protocol)
+{
+ __be16 dport;
+ __be16 sport = udp_flow_src_port(net, skb, 0, 0, false);
+ struct udphdr *udph; /* Our new UDP header */
+ struct guehdr *gueh; /* Our new GUE header */
+
+ skb_push(skb, sizeof(struct guehdr));
+
+ gueh = (struct guehdr *)skb->data;
+
+ gueh->control = 0;
+ gueh->version = 0;
+ gueh->hlen = 0;
+ gueh->flags = 0;
+ gueh->proto_ctype = *next_protocol;
+
+ skb_push(skb, sizeof(struct udphdr));
+ skb_reset_transport_header(skb);
+
+ udph = udp_hdr(skb);
+
+ dport = htons(atomic_read(&cp->dest->tun_port));
+ udph->dest = dport;
+ udph->source = sport;
+ udph->len = htons(skb->len);
+ udph->check = 0;
+
+ *next_protocol = IPPROTO_UDP;
+
+ return 0;
+}
+
/*
* IP Tunneling transmitter
*
@@ -1025,6 +1079,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
struct iphdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space needed */
int ret, local;
+ int tun_type, gso_type;

EnterFunction(10);

@@ -1046,6 +1101,16 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
*/
max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);

+ tun_type = atomic_read(&cp->dest->tun_type);
+
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
+ break;
+ default:
+ break;
+ }
+
/* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
@@ -1054,11 +1119,30 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
if (IS_ERR(skb))
goto tx_error;

- if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET, cp->af)))
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ gso_type = SKB_GSO_UDP_TUNNEL;
+ break;
+ default:
+ gso_type = __tun_gso_type_mask(AF_INET, cp->af);
+ break;
+ }
+
+ if (iptunnel_handle_offloads(skb, gso_type))
goto tx_error;

skb->transport_header = skb->network_header;

+ skb_set_inner_ipproto(skb, next_protocol);
+
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ ipvs_gue_encap(net, skb, cp, &next_protocol);
+ break;
+ default:
+ break;
+ }
+
skb_push(skb, sizeof(struct iphdr));
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1102,6 +1186,8 @@ int
ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
{
+ struct netns_ipvs *ipvs = cp->ipvs;
+ struct net *net = ipvs->net;
struct rt6_info *rt; /* Route to the other host */
struct in6_addr saddr; /* Source for tunnel */
struct net_device *tdev; /* Device to other host */
@@ -1112,10 +1198,11 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
struct ipv6hdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space needed */
int ret, local;
+ int tun_type, gso_type;

EnterFunction(10);

- local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
+ local = __ip_vs_get_out_rt_v6(ipvs, cp->af, skb, cp->dest,
&cp->daddr.in6,
&saddr, ipvsh, 1,
IP_VS_RT_MODE_LOCAL |
@@ -1134,17 +1221,46 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
*/
max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);

+ tun_type = atomic_read(&cp->dest->tun_type);
+
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
+ break;
+ default:
+ break;
+ }
+
skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
&next_protocol, &payload_len,
&dsfield, &ttl, NULL);
if (IS_ERR(skb))
goto tx_error;

- if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET6, cp->af)))
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ gso_type = SKB_GSO_UDP_TUNNEL;
+ break;
+ default:
+ gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
+ break;
+ }
+
+ if (iptunnel_handle_offloads(skb, gso_type))
goto tx_error;

skb->transport_header = skb->network_header;

+ skb_set_inner_ipproto(skb, next_protocol);
+
+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ ipvs_gue_encap(net, skb, cp, &next_protocol);
+ break;
+ default:
+ break;
+ }
+
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1167,7 +1283,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,

ret = ip_vs_tunnel_xmit_prepare(skb, cp);
if (ret == NF_ACCEPT)
- ip6_local_out(cp->ipvs->net, skb->sk, skb);
+ ip6_local_out(net, skb->sk, skb);
else if (ret == NF_DROP)
kfree_skb(skb);

--
2.21.0