Add IP_VS_SVC_F_SECURE_TCP to mark a virtual service for the
DoS-hardened TCP connection state table, and
IP_VS_CONN_F_SECURE_TCP to carry that capability on a connection
so the TCP state machine can select the hardened table for it.

The service flag is 0x0100: bits 0x0008/0x0010/0x0020 are the
scheduler bits, so leave 0x0040/0x0080 free for schedulers.

Set IP_VS_CONN_F_SECURE_TCP on every connection bound to a
destination whose service carries IP_VS_SVC_F_SECURE_TCP.

Signed-off-by: Adriano Cordova <[email protected]>
---
Changes in v2:
- Let IP_VS_SVC_F_SECURE_TCP be 0x0100, leaving 0x0040/0x0080 free for
  scheduler flags.
- Let IP_VS_CONN_F_SECURE_TCP be (1 << 17) and drop it from
  IP_VS_CONN_F_BACKUP_MASK.
- Set the flag in ip_vs_bind_dest() instead of at every ip_vs_conn_new()
  call site.

Changes in v3:
- Merge the uapi flag definition and the ip_vs_bind_dest() stamping into
  a single patch.

(no changes since v3)

 include/uapi/linux/ip_vs.h      | 2 ++
 net/netfilter/ipvs/ip_vs_conn.c | 4 ++++
 net/netfilter/ipvs/ip_vs_core.c | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/include/uapi/linux/ip_vs.h b/include/uapi/linux/ip_vs.h
index 2c37c6ac7525..ade170109ff4 100644
--- a/include/uapi/linux/ip_vs.h
+++ b/include/uapi/linux/ip_vs.h
@@ -27,6 +27,7 @@
 
 #define IP_VS_SVC_F_SCHED_SH_FALLBACK  IP_VS_SVC_F_SCHED1 /* SH fallback */
 #define IP_VS_SVC_F_SCHED_SH_PORT      IP_VS_SVC_F_SCHED2 /* SH use port */
+#define IP_VS_SVC_F_SECURE_TCP 0x0100          /* use the hardened TCP table */
 
 /*
  *      IPVS sync daemon states
@@ -105,6 +106,7 @@
 
 /* Flags that are not sent to backup server start from bit 16 */
 #define IP_VS_CONN_F_NFCT      (1 << 16)       /* use netfilter conntrack */
+#define IP_VS_CONN_F_SECURE_TCP        (1 << 17)       /* use the hardened TCP 
table */
 
 /* Connection flags from destination that can be changed by user space */
 #define IP_VS_CONN_F_DEST_MASK (IP_VS_CONN_F_FWD_MASK | \
diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index 6fa3e1dc534c..0b465298b64b 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -1090,6 +1090,7 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest 
*dest)
 {
        unsigned int conn_flags;
        __u32 flags;
+       struct ip_vs_service *svc;
 
        /* if dest is NULL, then return directly */
        if (!dest)
@@ -1102,6 +1103,9 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest 
*dest)
        if (cp->protocol != IPPROTO_UDP)
                conn_flags &= ~IP_VS_CONN_F_ONE_PACKET;
        flags = cp->flags;
+       svc = rcu_dereference(dest->svc);
+       if (svc && (svc->flags & IP_VS_SVC_F_SECURE_TCP))
+               flags |= IP_VS_CONN_F_SECURE_TCP;
        /* Bind with the destination and its corresponding transmitter */
        if (flags & IP_VS_CONN_F_SYNC) {
                /* Synced conns are hashed, so they can not get this flag */
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index ba0957798bad..aa8a3a964ffd 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -784,6 +784,9 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff 
*skb,
                                      IP_VS_CONN_F_ONE_PACKET : 0;
                union nf_inet_addr daddr = { .all = { 0, 0, 0, 0 } };
 
+               if (svc->flags & IP_VS_SVC_F_SECURE_TCP)
+                       flags |= IP_VS_CONN_F_SECURE_TCP;
+
                /* create a new connection entry */
                IP_VS_DBG(6, "%s(): create a cache_bypass entry\n", __func__);
                {
-- 
2.51.0


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