arch-gnu-linux/posix-socket.c: Fix order of EVT/GEN frames reception

This patch fixes a bug related to reception order of msgs. Sync msgs are defined as "Event" messages and FollowUp are "General" messages, and we need to handle them in the very same order they were sent (i.e. FollowUp is after Sync). With the implementation prior to this patch, we tried to serve Event and General alternatively. Now we always check for Event frames before General ones. I didn't find, in ieee spec, whether they cleary state that Event class is higher priority, at reception, with respect to General, but this is likely to be in this way, since Event messages are those needing the most precise timing. For more information about PTP message classes, see IEEE 1588v2, pag. 17, paragraph 6.4. Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>

arch-gnu-linux/posix-socket.c: Fix order of EVT/GEN frames reception
This patch fixes a bug related to reception order of msgs. Sync msgs are defined as "Event" messages and FollowUp are "General" messages, and we need to handle them in the very same order they were sent (i.e. FollowUp is after Sync). With the implementation prior to this patch, we tried to serve Event and General alternatively. Now we always check for Event frames before General ones. I didn't find, in ieee spec, whether they cleary state that Event class is higher priority, at reception, with respect to General, but this is likely to be in this way, since Event messages are those needing the most precise timing. For more information about PTP message classes, see IEEE 1588v2, pag. 17, paragraph 6.4. Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
f760717f · Aurelio Colosimo · 01290482 · f760717f · f760717f
Commit f760717f authored Mar 26, 2013 by Aurelio Colosimo
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posix-socket.c arch-gnu-linux/posix-socket.c +4 -10

posix.h arch-gnu-linux/posix.h +0 -1

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--- a/arch-gnu-linux/posix-socket.c
+++ b/arch-gnu-linux/posix-socket.c
@@ -105,16 +105,10 @@ static int posix_net_recv(struct pp_instance *ppi, void *pkt, int len,
 		return ret;
 	}

-	/* else: UDP, we can return one frame only, so swap priority */
-	if (POSIX_ARCH(ppi)->rcv_switch) {
-		ch1 = &(NP(ppi)->ch[PP_NP_GEN]);
-		ch2 = &(NP(ppi)->ch[PP_NP_EVT]);
-	} else {
-		ch1 = &(NP(ppi)->ch[PP_NP_EVT]);
-		ch2 = &(NP(ppi)->ch[PP_NP_GEN]);
-	}
-
-	POSIX_ARCH(ppi)->rcv_switch = !POSIX_ARCH(ppi)->rcv_switch;
+	/* else: UDP, we can return one frame only, always handle EVT msgs
+	 * before GEN */
+	ch1 = &(NP(ppi)->ch[PP_NP_EVT]);
+	ch2 = &(NP(ppi)->ch[PP_NP_GEN]);

 	ret = -1;
 	if (ch1->pkt_present)

--- a/arch-gnu-linux/posix.h
+++ b/arch-gnu-linux/posix.h
@@ -9,7 +9,6 @@
 #define POSIX_ARCH(ppi) ((struct posix_arch_data *)(ppi->arch_data))
 struct posix_arch_data {
 	struct timeval tv;
-	int rcv_switch; /* flag for event / general receive order */
 };

 extern int posix_net_check_pkt(struct pp_instance *ppi, int delay_ms);