Re: [lwip-users] PING App Issues [RAW]

[HM2]

lwip1.3  I downloaded the contrib files back a couple weeks ago from CVS.
But the ping.c file date was March 23, 2008.  I just checked the files
again, and the site still has files from 2008.


----- Original Message ----- 
From: <address@hidden>
To: "Mailing list for lwIP users" <address@hidden>
Sent: Sunday, May 10, 2009 12:01 AM
Subject: Re: [lwip-users] PING App Issues [RAW]


> The pbuf leak might still be in there, but the checksum generation has
> already been corrected in CVS (I assume you are using 1.3.0, you don't
> tell that).
>
> Simon
>
>
> HM2 wrote:
> > I ran into a number of issues using the PING app from the contrib
section.
> > I am using RAW mode.  The PING app just did requests, so I wrote some
> > additional code for it to handle replies now as well.  That seems to
work
> > fine,  but  working on this I then noticed some other issues.  The
previous
> > first routine ping_prepare_echo() was doing the checksum at the wrong
place.
> > It needs to be last, after the sample data is built, since the checksum
> > covers that area as well.  Also, there was a pbuf leak in the
ping_recv()
> > routine.  It needs to free the main pbuf, or after enough pings, the
pool is
> > consumed.  The significant portions of my code changes are given below.
> >
> > Regards,  Chris.
> >
> >
> > // Prepare a ECHO ICMP REQUEST
> > static void ping_prepare_echo( struct icmp_echo_hdr *iecho, u16_t len) {
> >   int i;
> >   ICMPH_TYPE_SET(iecho,ICMP_ECHO);
> >   ICMPH_CODE_SET(iecho, 0);
> >   iecho->chksum = 0;
> >   iecho->id     = PING_ID;
> >   iecho->seqno  = htons(++ping_seq_num);
> >   // fill the additional data buffer with some data
> >   for(i = 0; i < PING_DATA_SIZE; i++) {
> >     ((char*)iecho)[sizeof(struct icmp_echo_hdr) + i] = i+48; // easier
to
> > look at ASCII
> >     }
> >   iecho->chksum = inet_chksum(iecho, len); // CNS, checksum needs to be
done
> > after data
> > }
> >
> >
> > // CNS, Prepare a ECHO REPLY
> > static void ping_prepare_reply( struct icmp_echo_hdr *ireply, u16_t len,
> > struct icmp_echo_hdr *iecho) {
> >    int i,m;
> >    ICMPH_TYPE_SET(ireply,ICMP_ER); // echo reply
> >    ICMPH_CODE_SET(ireply, 0);
> >    ireply->id     = iecho->id;  // copy ID from request
> >    ireply->seqno  = iecho->seqno;  // copy seqno from request
> >    ireply->chksum = 0;
> >    // copy data from echo request
> >  // Ping Size may not be standard, so calc from actual msg size and sub
> > header
> >  m = len-sizeof(struct icmp_echo_hdr);
> >    for(i = 0; i < m; i++) {
> >      ((char*)ireply)[sizeof(struct icmp_echo_hdr) + i] =
> > ((char*)iecho)[sizeof(struct icmp_echo_hdr) + i];
> >      }
> >    ireply->chksum = inet_chksum(ireply, len);
> > }
> >
> >
> > // Ping Rcve using the raw ip
> > static u8_t ping_recv(void *arg, struct raw_pcb *pcb, struct pbuf *p,
struct
> > ip_addr *addr) {
> >  LWIP_UNUSED_ARG(arg);
> >    struct icmp_echo_hdr *iecho;
> >    struct icmp_echo_hdr *ireply;
> >  struct pbuf *r;
> >  int hlen;
> >  struct in_addr val;
> >
> >   if (pbuf_header( p, -PBUF_IP_HLEN)==0) {
> >     iecho = p->payload;
> >  // CNS this section generates REPLY to any ECHO REQUEST
> >     if (iecho->_type_code == ICMP_ECHO) {  // rcvd echo, generate echo
reply
> >   hlen = p->tot_len;      // length of ping request, typ 40 bytes
> >   r = pbuf_alloc(PBUF_IP, hlen, PBUF_RAM); // new pbuf
> >     if (r!=NULL) {
> >    ireply=r->payload;
> >       ping_prepare_reply(ireply, hlen,iecho);
> >       raw_sendto(pcb, r, addr);
> >    pbuf_free(r);       // dump new pbuf
> >    r = NULL;
> >    }
> >   }
> >  // this section handles replies to our ECHO REQUEST
> >     if ((iecho->id == PING_ID) && (iecho->seqno == htons(ping_seq_num)))
{
> >   val.s_addr = addr->addr;
> >     printf("Ping Reply %s\n", inet_ntoa(val));
> >        LWIP_DEBUGF( PING_DEBUG, ("ping: recv "));
> >        ip_addr_debug_print(PING_DEBUG, addr);
> >        LWIP_DEBUGF( PING_DEBUG, (" %lu ms\n", (sys_now()-ping_time)));
> >        // do some ping result processing
> >        PING_RESULT(1);
> >        }
> >     }
> >   pbuf_free(p); // CNS, free the org pbuf, otherwise leak!
> >   p=NULL;
> >   return 1;  // eat the event
> > }
> >
> >
> >
> >
> >
> >
> >
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> >
> >
>
>
>
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