From 3f288faeec7a7345b59dfa9cbecf8507008c8a6b Mon Sep 17 00:00:00 2001
From: gaoxingwang <gxw94linux@163.com>
Date: Tue, 1 Nov 2022 11:14:05 +0800
Subject: [PATCH] add sysctl to change opcode dynamic

---
 src/toa.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 src/toa.h |  3 ---
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/toa.c b/src/toa.c
index 931607d..2de3442 100644
--- a/src/toa.c
+++ b/src/toa.c
@@ -15,12 +15,16 @@
  * GNU General Public License for more details.
  *
  */
+#include <net/net_namespace.h>
 #include "toa.h"
 /*
  *    TOA: Address is a new TCP Option
  *    Address include ip+port, Now support IPV4 and IPV6
  */
 
+static unsigned int sysctl_toa_opcode_v4 = 254;
+static unsigned int sysctl_toa_opcode_v6 = 254;
+
 #if  defined(CONFIG_ARM64)
 /*
   * ARM64 interface
@@ -436,7 +440,7 @@ static void *get_toa_data(int af, struct sk_buff *skb, int *nat64)
                 if (opsize > length)
                     /* don't parse partial options */
                     return NULL;
-                if (TCPOPT_TOA == opcode &&
+                if (sysctl_toa_opcode_v4 == opcode &&
                     TCPOLEN_IP4_TOA == opsize) {
 
                     struct toa_ip4_data tdata;
@@ -479,7 +483,7 @@ static void *get_toa_data(int af, struct sk_buff *skb, int *nat64)
                 }
 
 #if (defined(TOA_IPV6_ENABLE) || defined(TOA_NAT64_ENABLE))
-                if (TCPOPT_TOA == opcode &&
+                if (sysctl_toa_opcode_v6 == opcode &&
                     TCPOLEN_IP6_TOA == opsize) {
                     struct toa_ip6_data *ptr_toa_ip6;
                     struct toa_ip6_entry *ptr_toa_entry =
@@ -552,7 +556,7 @@ inet_getname_toa(struct socket *sock, struct sockaddr *uaddr,
         if (sk_data_ready_addr == (unsigned long) sk->sk_data_ready &&
             !sock_flag(sk, SOCK_NAT64)) {
             memcpy(&tdata, &sk->sk_user_data, sizeof(tdata));
-            if (TCPOPT_TOA == tdata.opcode &&
+            if (sysctl_toa_opcode_v4 == tdata.opcode &&
                 TCPOLEN_IP4_TOA == tdata.opsize) {
                 TOA_INC_STATS(ext_stats, GETNAME_TOA_OK_CNT);
                 TOA_DBG("inet_getname_toa: set new sockaddr, ip "
@@ -639,7 +643,7 @@ inet64_getname_toa(struct sock *sk, int cmd, void __user *user, int *len)
             ptr_ip6_entry = sk->sk_user_data;
             ptr_ip6_data = &ptr_ip6_entry->toa_data;
 
-            if (TCPOPT_TOA == ptr_ip6_data->opcode &&
+            if (sysctl_toa_opcode_v6 == ptr_ip6_data->opcode &&
                 TCPOLEN_IP6_TOA == ptr_ip6_data->opsize) {
                 TOA_INC_STATS(ext_stats, GETNAME_TOA_OK_CNT);
                 TOA_DBG("inet64_getname_toa: set new sockaddr, ip "
@@ -720,7 +724,7 @@ inet6_getname_toa(struct socket *sock, struct sockaddr *uaddr,
             struct toa_ip6_data* ptr_ip6_data = &ptr_ip6_entry->toa_data;
 
             if (sk == ptr_ip6_entry->sk &&
-                TCPOPT_TOA == ptr_ip6_data->opcode &&
+                sysctl_toa_opcode_v6 == ptr_ip6_data->opcode &&
                 TCPOLEN_IP6_TOA == ptr_ip6_data->opsize) {
                 TOA_INC_STATS(ext_stats, GETNAME_TOA_OK_CNT);
                 TOA_DBG("inet6_getname_toa: set new sockaddr, ip "
@@ -1124,6 +1128,38 @@ static void proc_net_remove(struct net *net, const char *name)
 }
 #endif
 
+static unsigned int byte_min = 0;
+static unsigned int byte_max = 255;
+static struct ctl_table toa_v4_sysctl_table[] = {
+    {
+        .procname = "toa_opcode_v4",
+        .data = &sysctl_toa_opcode_v4,
+        .maxlen = sizeof(unsigned int),
+        .mode = 0644,
+        .proc_handler = proc_dointvec_minmax,
+        .extra1 = &byte_min,
+        .extra2 = &byte_max,
+    },
+    {
+    },
+};
+
+static struct ctl_table toa_v6_sysctl_table[] = {
+    {
+        .procname = "toa_opcode_v6",
+        .data = &sysctl_toa_opcode_v6,
+        .maxlen = sizeof(unsigned int),
+        .mode = 0644,
+        .proc_handler = proc_dointvec_minmax,
+        .extra1 = &byte_min,
+        .extra2 = &byte_max,
+    },
+    {
+    },
+};
+static struct ctl_table_header *toa_v4_sysctl_header = NULL;
+static struct ctl_table_header *toa_v6_sysctl_header = NULL;
+
 /* module init */
 static int __init
 toa_init(void)
@@ -1140,6 +1176,16 @@ toa_init(void)
 
     TOA_INFO("TOA " TOA_VERSION " by qlb of iqiyi.\n");
 
+    toa_v4_sysctl_header = register_net_sysctl(&init_net, "net/ipv4", toa_v4_sysctl_table);
+    if (NULL == toa_v4_sysctl_header) {
+        TOA_INFO("register toa v4 sysctl failed\n");
+    }
+
+    toa_v6_sysctl_header = register_net_sysctl(&init_net, "net/ipv6", toa_v6_sysctl_table);
+    if (NULL == toa_v4_sysctl_header) {
+        TOA_INFO("register toa v6 sysctl failed\n");
+    }
+
     /* alloc statistics array for toa */
     ext_stats = alloc_percpu(struct toa_stat_mib);
     if (NULL == ext_stats)
@@ -1215,6 +1261,9 @@ toa_exit(void)
     unregister_kprobe(&kp);
 #endif
 
+    unregister_sysctl_table(toa_v4_sysctl_header);
+    unregister_sysctl_table(toa_v6_sysctl_header);
+
     proc_net_remove(&init_net, "toa_stats");
     if (NULL != ext_stats) {
         free_percpu(ext_stats);
diff --git a/src/toa.h b/src/toa.h
index 64095c3..6c64c61 100644
--- a/src/toa.h
+++ b/src/toa.h
@@ -61,9 +61,6 @@
             printk(KERN_INFO "TOA: " msg);    \
     } while (0)
 
-
-#define TCPOPT_TOA  254
-
 /* MUST be 4n !!!! */
 #define TCPOLEN_IP4_TOA 8        /* |opcode|size|ip+port| = 1 + 1 + 6 */
 #define TCPOLEN_IP6_TOA 20        /* |opcode|size|ip_of_v6+port| = 1 + 1 + 18 */
-- 
2.27.0