[PATCH v2] ipvs: allow tunneling with gue encapsulation

From: Jacky Hu
Date: Sat Mar 16 2019 - 02:07:15 EST


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@xxxxxxxxx>
---
include/net/ip_vs.h | 5 ++
include/uapi/linux/ip_vs.h | 17 +++++++
net/netfilter/ipvs/ip_vs_ctl.c | 20 +++++++-
net/netfilter/ipvs/ip_vs_xmit.c | 85 +++++++++++++++++++++++++++++++--
4 files changed, 122 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..b43297691337 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.
@@ -155,6 +162,9 @@ struct ip_vs_dest_user {
/* thresholds for active connections */
__u32 u_threshold; /* upper threshold */
__u32 l_threshold; /* lower threshold */
+
+ __u16 tun_type; /* tunnel type */
+ __be16 tun_port; /* tunnel port */
};


@@ -220,6 +230,9 @@ struct ip_vs_dest_entry {
__u32 u_threshold; /* upper threshold */
__u32 l_threshold; /* lower threshold */

+ __u16 tun_type; /* tunnel type */
+ __be16 tun_port; /* tunnel port */
+
__u32 activeconns; /* active connections */
__u32 inactconns; /* inactive connections */
__u32 persistconns; /* persistent connections */
@@ -392,6 +405,10 @@ 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..48509b03a5ea 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;
@@ -2869,6 +2873,8 @@ 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 +3178,10 @@ 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_u16(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 +3304,14 @@ 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 +3321,12 @@ 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_u16(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..3efb46a14163 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 */
@@ -989,6 +990,42 @@ static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
}
}

+static int
+__build_gue_header(struct net *net, struct sk_buff *skb,
+ struct ip_vs_conn *cp, __u8 *next_protocol)
+{
+ __be16 dport;
+ __be16 sport;
+ 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));
+ sport = udp_flow_src_port(net, skb, 0, 0, false);
+ 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 +1062,7 @@ 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);

@@ -1033,7 +1071,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
IP_VS_RT_MODE_NON_LOCAL |
IP_VS_RT_MODE_CONNECT |
IP_VS_RT_MODE_TUNNEL, &saddr, ipvsh);
- if (local < 0)
+ if (!cp->dest || local < 0)
goto tx_error;
if (local)
return ip_vs_send_or_cont(NFPROTO_IPV4, skb, cp, 1);
@@ -1046,6 +1084,13 @@ 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);
+ }
+
/* 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 +1099,23 @@ 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_IPIP:
+ gso_type = __tun_gso_type_mask(AF_INET, cp->af);
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ gso_type = SKB_GSO_UDP_TUNNEL;
+ }
+
+ if (iptunnel_handle_offloads(skb, gso_type))
goto tx_error;

skb->transport_header = skb->network_header;

+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ __build_gue_header(dev_net(tdev), skb, cp, &next_protocol);
+ }
+
skb_push(skb, sizeof(struct iphdr));
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -1112,6 +1169,7 @@ 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);

@@ -1121,7 +1179,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
IP_VS_RT_MODE_LOCAL |
IP_VS_RT_MODE_NON_LOCAL |
IP_VS_RT_MODE_TUNNEL);
- if (local < 0)
+ if (!cp->dest || local < 0)
goto tx_error;
if (local)
return ip_vs_send_or_cont(NFPROTO_IPV6, skb, cp, 1);
@@ -1134,17 +1192,36 @@ 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);
+ }
+
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_IPIP:
+ gso_type = __tun_gso_type_mask(AF_INET, cp->af);
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ gso_type = SKB_GSO_UDP_TUNNEL;
+ }
+
+ if (iptunnel_handle_offloads(skb, gso_type))
goto tx_error;

skb->transport_header = skb->network_header;

+ switch (tun_type) {
+ case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+ __build_gue_header(dev_net(tdev), skb, cp, &next_protocol);
+ }
+
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
--
2.21.0