dcdn-toa.patch

From cee6889685240558ebea795615539b7289070842 Mon Sep 17 00:00:00 2001
From: wangyetong <wangyetong@qiyi.com>
Date: Thu, 14 Sep 2023 15:33:42 +0800
Subject: [PATCH] added dcdn toa

---
 include/ipvs/conn.h        |  4 ++++
 include/ipvs/proto_tcp.h   |  2 ++
 src/ipvs/ip_vs_proto_tcp.c | 55 +++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/include/ipvs/conn.h b/include/ipvs/conn.h
index 843721e..78fb0ba 100644
--- a/include/ipvs/conn.h
+++ b/include/ipvs/conn.h
@@ -167,6 +167,10 @@ struct dp_vs_conn {
     /* connection redirect in fnat/snat/nat modes */
     struct dp_vs_redirect  *redirect;
 
+    /* dcdn toa found or not */
+    bool dcdn_found;
+    /* dcdn toa address */
+    struct in_addr    dcdn_addr;
 } __rte_cache_aligned;
 
 /* for syn-proxy to save all ack packet in conn before rs's syn-ack arrives */
diff --git a/include/ipvs/proto_tcp.h b/include/ipvs/proto_tcp.h
index 3d1515a..f0cf50c 100644
--- a/include/ipvs/proto_tcp.h
+++ b/include/ipvs/proto_tcp.h
@@ -28,6 +28,7 @@ enum {
     TCP_OPT_SACK_PERM   = 4,
     TCP_OPT_SACK        = 5,
     TCP_OPT_TIMESTAMP   = 8,
+    TCP_OPT_DCDN_ADDR   = 28,
     TCP_OPT_ADDR        = 254, /* non-standard */
 };
 
@@ -35,6 +36,7 @@ enum {
 #define TCP_OLEN_TIMESTAMP          10
 #define TCP_OLEN_IP4_ADDR           8
 #define TCP_OLEN_IP6_ADDR           20
+#define TOA_DCDN_IPV4               1
 
 #define TCP_OLEN_TSTAMP_ALIGNED     12
 #define TCP_OLEN_SACK_BASE          2
diff --git a/src/ipvs/ip_vs_proto_tcp.c b/src/ipvs/ip_vs_proto_tcp.c
index 6acbbca..5b185fa 100644
--- a/src/ipvs/ip_vs_proto_tcp.c
+++ b/src/ipvs/ip_vs_proto_tcp.c
@@ -441,6 +441,43 @@ static int tcp_in_add_proxy_proto(struct dp_vs_conn *conn, struct rte_mbuf *mbuf
     return proxy_proto_insert(&ppinfo, conn, mbuf, tcph, hdr_shift);
 }
 
+/* check dcdn toa option */
+static inline int tcp_in_check_toa(struct dp_vs_conn *conn, struct tcphdr *tcph, struct in_addr *addr)
+{
+    unsigned char *ptr;
+    int len;
+
+    ptr = (unsigned char *)(tcph + 1);
+    len = (tcph->doff << 2) - sizeof(struct tcphdr);
+
+    while (len > 0) {
+        int opcode = *ptr++;
+        int opsize;
+
+        switch (opcode) {
+        case TCP_OPT_EOL:
+            return EDPVS_NOTEXIST;
+        case TCP_OPT_NOP:
+            len--;
+            continue;
+        default:
+            opsize = *ptr++;
+            if (opsize < 2)    /* silly options */
+                return EDPVS_NOTEXIST;
+            if (opsize > len)
+                return EDPVS_NOTEXIST;    /* partial options */
+            if ((opcode == TCP_OPT_DCDN_ADDR)
+                    && (*ptr == TOA_DCDN_IPV4) && (opsize == TCP_OLEN_IP4_ADDR - 1) && addr) {
+                memcpy(addr, ptr + 1, sizeof(struct in_addr));
+                return EDPVS_OK;
+            }
+            ptr += opsize - 2;
+            len -= opsize;
+        }
+    }
+    return EDPVS_NOTEXIST;
+}
+
 static int tcp_in_add_toa(struct dp_vs_conn *conn, struct rte_mbuf *mbuf,
                           struct tcphdr *tcph)
 {
@@ -518,7 +555,10 @@ static int tcp_in_add_toa(struct dp_vs_conn *conn, struct rte_mbuf *mbuf,
 
     if (conn->af == AF_INET) {
         struct tcpopt_ip4_addr *toa_ip4 = (struct tcpopt_ip4_addr *)(tcph + 1);
-        toa_ip4->addr = conn->caddr.in;
+        if (conn->dcdn_found)
+            toa_ip4->addr = conn->dcdn_addr;
+        else
+            toa_ip4->addr = conn->caddr.in;
     }
     else {
         struct tcpopt_ip6_addr *toa_ip6 = (struct tcpopt_ip6_addr *)(tcph + 1);
@@ -842,6 +882,10 @@ static int tcp_fnat_in_handler(struct dp_vs_proto *proto,
     int af;             /* outbound af */
     int iphdrlen;
     int err, pp_hdr_shift = 0;
+    struct in_addr dcdn_addr;
+#ifdef CONFIG_DPVS_IPVS_DEBUG
+    char dcdn_buf[64];
+#endif
 
     af = tuplehash_out(conn).af;
     iphdrlen = ((AF_INET6 == af) ? ip6_hdrlen(mbuf): ip4_hdrlen(mbuf));
@@ -866,6 +910,15 @@ static int tcp_fnat_in_handler(struct dp_vs_proto *proto,
     if (th->syn && !th->ack) {
         tcp_in_remove_ts(th);
         tcp_in_init_seq(conn, mbuf, th);
+        if (tcp_in_check_toa(conn, th, &dcdn_addr) == EDPVS_OK) {
+            conn->dcdn_found = true;
+            conn->dcdn_addr = dcdn_addr;
+#ifdef CONFIG_DPVS_IPVS_DEBUG
+            inet_ntop(AF_INET, &dcdn_addr, dcdn_buf, sizeof(dcdn_buf));
+            RTE_LOG(DEBUG, IPVS, "get dcdn toa addr %s\n", dcdn_buf);
+#endif
+        }
+        tcp_in_add_toa(conn, mbuf, th);
     }
 
     /* Add toa/proxy_protocol to the first data packet */
-- 
1.8.3.1