[lwip-devel] Some notes about lwip 1.3.2 RC1

[Iordan Neshev]

Hello,
I'm very glad to see 1.3.2 RC1 out.

Here is a short list with notes:

\src\netif\ppp\ppp.c:

   * line 169: Jabobsen should be JaCobsen
   * line 312 and line 331: LWIP_UNUSED_ARG(pc); is missing
     in pppLinkTerminated() and pppLinkDown() respectively.
     This leads to compiler warning when PPPOE_SUPPORT is NOT enabled.
    The proper place is under  "#if PPPOS_SUPPORT" in both functions if
   we insist to be accurate but on the top of the function (beween
   PPPControl *pc = .... and the debug message looks better.
     Place it wherever you prefer.
  
   * line 394: I guess it's a good idea to add a note above line 394
  
   /* Note: replace both NULLs with valid (pointers to) strings if you
      need to authorize with user name and password respectively */
   pppSetAuth(PPPAUTHTYPE_NONE, NULL, NULL);
  
   Somebody may find it useful. It took me some time to make sure that 
this is
   the right place to supply them and not somewhere else.
  
   *line 525: add a note after lcp_init(pd); I propose something like
   /* redundant, this is already done by ppp.c:pppInit() { ... 
(*protp->init)(i);...} Leaved here for clarity*/
   To be honest, I prefer not to remove the explicit initialization of 
lcp here
   because it looks logical to me and may save us if later someone 
decides to change anything anywhere.
   On the other hand, the note is too long and can be easily ignored 
(sorry for the noise if you decide so)

   *line 564: replace
   if (pc->errCode) {
     pd = pc->errCode;
   } else {
     pd = PPPERR_CONNECT;
   }
  
   with
  
   pd = (pc->errCode ? pc->errCode : PPPERR_CONNECT); /* use pd as 
return value */
  
   * line 660: replace
   if (pc->errCode) {
     pd = pc->errCode;
   } else {
     pd = PPPERR_CONNECT;
   }
  
   with
  
   pd = (pc->errCode ? pc->errCode : PPPERR_CONNECT);
  
   The last 2 changes just make the source shorter, nothing more; ppp.c 
too long and hard to read
  
   *line 1325:
   I think this is missing:

 #if LWIP_NETIF_STATUS_CALLBACK
 netif_set_status_callback(netif, pppnetif_status_callback);
 #endif
 #if LWIP_NETIF_LINK_CALLBACK
 netif_set_link_callback(netif, pppnetif_link_callback);
 #endif

   IMHO it's better to leave it for 1.4. This is related to "patch 
#6901: PPP callback with netif",
   so I'll make a note there. Btw I'm not sure which callback should be 
called first.
  
   *line 1388: add a function call

   pc->if_up = 0;
   netif_set_down(&pc->netif); // <-- this line is missing
   netif_remove(&pc->netif);
  
   This needs discussion. Everybody who rely on the status and link 
callbacks
   should think about this. It works for me.

  
   *line 1553:
   ....
   out:
 PPPDEBUG((LOG_DEBUG, "pppMain: unit %d: linkStatusCB=%lx 
errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));

 if(pc->linkStatusCB) {
   pc->linkStatusCB(pc->linkStatusCtx, pc->errCode ? pc->errCode : 
PPPERR_PROTOCOL, NULL);
 }
 /// ----> this is missing
 if (outpacket_buf[pd]) {
   mem_free(outpacket_buf[pd]);
 }
 /// <----
 pc->openFlag = 0;
} // (end of pppMain())
  
   This needs serious discussion. I can *not* confirm that this works.
   So far my investigation shows that we need to check one more 
condition before calling
   mem_free: the .used field of the mem struct must be != 0. 
Unfortunately it is not
   directly accessible through outpacket_buf[pd]. A dedicated function 
(based on mem_free),
   that returns the value of .used is needed.
   Should I file a bug about this _after_ 1.3.2 is released?

\src\netif\ppp\ipcp.c:

   *line 192: add "static" in front of
   "char *_inet_ntoa(u32_t n)"
   I can confirm that this works.
   Otherwise we should consider using \core\ipv4\init.c:*inet_ntoa(). 
The second needs discussion (-> lwip 1.4)
  
\src\netif\ppp\fsm.c:
   * line 556: change the debug message by adding "UNHANDLED"
     FSMDEBUG((LOG_INFO, "%s: UNHANDLED Timeout event in state %d (%s)!\n",
   I'm currently solving a problem and this one seems related to it. 
The default case of the
   corresponding switch is a potential source of bugs.

\src\core\tcp_in.c

       *line 337:
       TCP_EVENT_RECV(pcb, NULL, ERR_OK, err);
       A note may be added:
       /* the NULL argument causes compiler warning (unreachable code) 
that can be safely ignored */
       I spent some time to find out why this happens. May be helpful 
for somebody.
  
  
       tcp.in:tcp_timewait_input()
      
       *lines 690, 707, 718, 728: Add description in the debug messages 
what the current state is:
           ("(FIN_WAIT_1)TCP connection closed %"U16_F" -> 
%"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
           LWIP_DEBUGF(TCP_DEBUG, ("(FIN_WAIT_2)TCP connection closed 
%"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
           LWIP_DEBUGF(TCP_DEBUG, ("(FIN_WAIT_2)TCP connection closed 
%"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
           LWIP_DEBUGF(TCP_DEBUG, ("(CLOSING) TCP connection closed 
%"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
           LWIP_DEBUGF(TCP_DEBUG, ("(LAST_ACK) TCP connection closed 
%"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
          
       It's possible to use tcp_debug_state_str(), but this would make 
the source less readable.
          
       *lines 814, 820: there are 12 spaces that should be removed. 
They are invisible until the file is compared against
                          some older version.
      
\src\core\mem.c

   *line 175:    add LWIP_HEAP_RAM_SECTION to specify where the heap 
should be placed
   static LWIP_HEAP_RAM_SECTION u8_t ram_heap[MEM_SIZE_ALIGNED + 
(2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT];
      
   then this should be added either in opt.h or a couple of lines upper 
in mem.c:
  
   #ifndef LWIP_HEAP_RAM_SECTION
     #define LWIP_HEAP_RAM_SECTION
   #endif
  
   Then somewhere (eventually lwipopts.h) the user may add (as I did):
   #define LWIP_HEAP_RAM_SECTION        __attribute__ ((section 
(".ethram")))
  
   Of course the linker has to know what .ethram is. That's haw I managed
   to utilize the RAM which is otherwise used by the integrated 
Ethernet controller in
   LPC2368 and in my application would be lost. This change will not 
affect in any way
   users that do not want to specify the memory location.
  
   Greetings,
   Iordan.