mtpd: l2tp: Fix endianness issues in log prints

Tunnel and session variables are obtained from network, thus are stored
in network endianness. Although this fact is mentioned in this comment:

    // To avoid unnecessary endianness conversions, tunnels, sessions,
    // attributes, and values are all accessed in network order

those variables are not being converted to host endianness when printing.

So convert them to host endianness when printing. Also change the type of
those variables to __be16 so we can distinguish them easier.

Change-Id: If4a147929fbc79ada51ce5c4f6a1e929d76267aa
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>

1 files changed, 20 insertions, 16 deletions

diff --git a/l2tp.c b/l2tp.c
index 7dd550a..c2aa4c9 100644
--- a/l2tp.c
+++ b/l2tp.c
@@ -31,6 +31,7 @@
 #include <arpa/inet.h>
 #include <linux/netdevice.h>
 #include <linux/if_pppox.h>
+#include <linux/types.h>
 #include <openssl/md5.h>
 
 #include "mtpd.h"
@@ -89,11 +90,11 @@ static char *messages[] = {
 #define ATTRIBUTE_HEADER_SIZE   6
 #define MAX_ATTRIBUTE_SIZE      1024
 
-static uint16_t local_tunnel;
-static uint16_t local_session;
+static __be16 local_tunnel;
+static __be16 local_session;
 static uint16_t local_sequence;
-static uint16_t remote_tunnel;
-static uint16_t remote_session;
+static __be16 remote_tunnel;
+static __be16 remote_session;
 static uint16_t remote_sequence;
 
 static uint16_t state;
@@ -321,7 +322,8 @@ static int l2tp_connect(char **arguments)
         local_tunnel = random();
     }
 
-    log_print(DEBUG, "Sending SCCRQ (local_tunnel = %d)", local_tunnel);
+    log_print(DEBUG, "Sending SCCRQ (local_tunnel = %u)",
+              (unsigned)ntohs(local_tunnel));
     state = SCCRQ;
     set_message(0, SCCRQ);
     add_attribute_u16(PROTOCOL_VERSION, htons(0x0100));
@@ -412,8 +414,8 @@ static void answer_challenge()
 static int l2tp_process()
 {
     uint16_t sequence = local_sequence;
-    uint16_t tunnel = 0;
-    uint16_t session = 0;
+    __be16 tunnel = 0;
+    __be16 session = 0;
 
     if (!recv_packet(&session)) {
         return acknowledged ? 0 : TIMEOUT_INTERVAL;
@@ -427,8 +429,8 @@ static int l2tp_process()
                 if (get_attribute_u16(ASSIGNED_TUNNEL, &tunnel) && tunnel &&
                         verify_challenge()) {
                     remote_tunnel = tunnel;
-                    log_print(DEBUG, "Received SCCRP (remote_tunnel = %d) -> "
-                            "Sending SCCCN", remote_tunnel);
+                    log_print(DEBUG, "Received SCCRP (remote_tunnel = %u) -> "
+                            "Sending SCCCN", (unsigned)ntohs(remote_tunnel));
                     state = SCCCN;
                     set_message(0, SCCCN);
                     answer_challenge();
@@ -445,8 +447,8 @@ static int l2tp_process()
             if (state == ICRQ && session == local_session) {
                 if (get_attribute_u16(ASSIGNED_SESSION, &session) && session) {
                     remote_session = session;
-                    log_print(DEBUG, "Received ICRP (remote_session = %d) -> "
-                            "Sending ICCN", remote_session);
+                    log_print(DEBUG, "Received ICRP (remote_session = %u) -> "
+                            "Sending ICCN", (unsigned)ntohs(remote_session));
                     state = ICCN;
                     set_message(remote_session, ICCN);
                     add_attribute_u32(CONNECT_SPEED, htonl(100000000));
@@ -467,8 +469,8 @@ static int l2tp_process()
 
         case CDN:
             if (session && session == local_session) {
-                log_print(DEBUG, "Received CDN (local_session = %d)",
-                        local_session);
+                log_print(DEBUG, "Received CDN (local_session = %u)",
+                        (unsigned)ntohs(local_session));
                 log_print(INFO, "Remote server hung up");
                 return -REMOTE_REQUESTED;
             }
@@ -484,7 +486,8 @@ static int l2tp_process()
                     local_session = random();
                 }
                 log_print(DEBUG, "Received %s -> Sending ICRQ (local_session = "
-                        "%d)", messages[incoming.message], local_session);
+                        "%u)", messages[incoming.message],
+                        (unsigned)ntohs(local_session));
                 log_print(INFO, "Tunnel established");
                 state = ICRQ;
                 set_message(0, ICRQ);
@@ -513,8 +516,9 @@ static int l2tp_process()
             /* Since we run pppd as a client, it does not makes sense to
              * accept ICRQ or OCRQ. Always send CDN with a proper error. */
             if (get_attribute_u16(ASSIGNED_SESSION, &session) && session) {
-                log_print(DEBUG, "Received %s (remote_session = %d) -> "
-                        "Sending CDN", messages[incoming.message], session);
+                log_print(DEBUG, "Received %s (remote_session = %u) -> "
+                        "Sending CDN", messages[incoming.message],
+                        (unsigned)ntohs(session));
                 set_message(session, CDN);
                 add_attribute_u32(RESULT_CODE, htonl(0x00020006));
                 add_attribute_u16(ASSIGNED_SESSION, 0);