[lwip-users] SLIP bug

[marek]

Hello

I have used two network interfaces: ETHERNET and SLIP, I pinging them both
with large data size (about 1k to 1,4kB) and I think that function
slipif_input lose pbufs.
That is old code (from splip_input):

[...]
default:
      if (p == NULL) {
  LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
  p = pbuf_alloc(PBUF_LINK, PBUF_POOL_BUFSIZE, PBUF_POOL);

  if (p == NULL) {
    LINK_STATS_INC(link.drop);
    LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
  }

  if (q != NULL) {
    pbuf_cat(q, p);
  } else {
    q = p;
  }
      }
      if (p != NULL && recved < MAX_SIZE) {
  ((u8_t *)p->payload)[i] = c;
  recved++;
  i++;
  if (i >= p->len) {
    i = 0;
    p = NULL;
  }
[...]

what if the first pbuf was allocted, but the others could not ?
In that code it seem happy with that.
I think that If we cannot alloc the pbuf we have to free previously
allocated (q) pbufs and return from function with NULL.

that's my code:

[...]
default:
      if (p == NULL) {
  LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
  p = pbuf_alloc(PBUF_LINK, PBUF_POOL_BUFSIZE, PBUF_POOL);

  if (p == NULL) {
    LINK_STATS_INC(link.drop);
    LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
    pbuf_free(q);
    return NULL;
 }

  if (q != NULL) {
    pbuf_cat(q, p);
  } else {
    q = p;
  }
      }
      if (p != NULL && recved < MAX_SIZE) {
  ((u8_t *)p->payload)[i] = c;
  recved++;
  i++;
  if (i >= p->len) {
    i = 0;
    p = NULL;
  }
[...]


Is I am right  Leon ?