Hello Charles,
On Fri, Apr 11, 2014 at 12:13:02PM +0000, l...@moog.com wrote: > Sylvain, > > I applied the new patch, but the following statement always cause Data > Abort exception run-time error. No matter I set ETH_PAD_SIZE to 0 or > 2. The good thing is my compiler doesn't generate any error message > for the new patch. > > *((ppp_pcb**)payload) = pcb; Yeah, of course, there is an alignment problem here, pbuf->payload might be unaligned, here is a new patch with an helper packed struct which should fix the issue. It was fine with a PBUF_RAW because the pointer was put deliberately in front of the buffer, buffer which was allocated on alignment by lwIP. You don't need to set ETH_PAD_SIZE, this is not necessary. > Another thing I am not so sure is the macro PPP_USE_PBUF_RAM. I always > set it to 1 in lwipopts.h, but I think the default is set to 0 in > opt.h. Am I doing the right thing? Yes!, if you have a heap PPP_USE_PBUF_RAM is the option you should use, it allows you to use a smaller PBUF_POOL_BUFSIZE. Sylvain
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index 594d18c..7e4f632 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -1529,6 +1529,22 @@ ppp_drop(ppp_pcb_rx *pcrx)
snmp_inc_ifindiscards(&pcb->netif);
}
+/** PPPoS input helper struct, must be packed since it is stored
+ * to pbuf->payload, which might be unaligned. */
+#if PPP_INPROC_MULTITHREADED
+#ifdef PACK_STRUCT_USE_INCLUDES
+# include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct pppos_input_header {
+ PACK_STRUCT_FIELD(ppp_pcb *pcb);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+# include "arch/epstruct.h"
+#endif
+#endif /* PPP_INPROC_MULTITHREADED */
+
/** Pass received raw characters to PPPoS to be decoded. This function is
* thread-safe and can be called from a dedicated RX-thread or from a main-loop.
*
@@ -1704,7 +1720,15 @@ pppos_input(ppp_pcb *pcb, u_char *s, int l)
}
}
/* If we haven't started a packet, we need a packet header. */
+#if IP_FORWARD || LWIP_IPV6_FORWARD
+ /* If IP forwarding is enabled we are using a PBUF_LINK packet type so
+ * the packet is being allocated with enough header space to be
+ * forwarded (to Ethernet for example).
+ */
+ next_pbuf = pbuf_alloc(PBUF_LINK, 0, PBUF_POOL);
+#else /* IP_FORWARD || LWIP_IPV6_FORWARD */
next_pbuf = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
+#endif /* IP_FORWARD || LWIP_IPV6_FORWARD */
if (next_pbuf == NULL) {
/* No free buffers. Drop the input packet and let the
* higher layers deal with it. Continue processing
@@ -1716,15 +1740,27 @@ pppos_input(ppp_pcb *pcb, u_char *s, int l)
break;
}
if (pcrx->in_head == NULL) {
- u8_t *payload = next_pbuf->payload;
+ u8_t *payload;
+ /* pbuf_header() used below is only trying to put PPP headers
+ * before the current payload pointer if there is enough space
+ * in the pbuf to do so. Therefore we don't care if it fails,
+ * but if it fail we have to set len to the size used by PPP headers.
+ */
#if PPP_INPROC_MULTITHREADED
- *((ppp_pcb**)payload) = pcb;
- payload += sizeof(ppp_pcb*);
- next_pbuf->len += sizeof(ppp_pcb*);
+ if (pbuf_header(next_pbuf, +sizeof(struct pppos_input_header) +sizeof(pcrx->in_protocol))) {
+ next_pbuf->len += sizeof(struct pppos_input_header) + sizeof(pcrx->in_protocol);
+ }
+ payload = next_pbuf->payload;
+ ((struct pppos_input_header*)payload)->pcb = pcb;
+ payload += sizeof(struct pppos_input_header);
+#else /* PPP_INPROC_MULTITHREADED */
+ if (pbuf_header(next_pbuf, +sizeof(pcrx->in_protocol))) {
+ next_pbuf->len += sizeof(pcrx->in_protocol);
+ }
+ payload = next_pbuf->payload;
#endif /* PPP_INPROC_MULTITHREADED */
*(payload++) = pcrx->in_protocol >> 8;
*(payload) = pcrx->in_protocol & 0xFF;
- next_pbuf->len += sizeof(pcrx->in_protocol);
pcrx->in_head = next_pbuf;
}
pcrx->in_tail = next_pbuf;
@@ -1749,8 +1785,8 @@ static void pppos_input_callback(void *arg) {
struct pbuf *pb = (struct pbuf*)arg;
ppp_pcb *pcb;
- pcb = *((ppp_pcb**)pb->payload);
- if(pbuf_header(pb, -(s16_t)sizeof(ppp_pcb*))) {
+ pcb = ((struct pppos_input_header*)pb->payload)->pcb;
+ if(pbuf_header(pb, -(s16_t)sizeof(struct pppos_input_header))) {
LWIP_ASSERT("pbuf_header failed\n", 0);
goto drop;
}
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