2010/8/11 Simon Horman <ho...@verge.net.au>:
>> > http://hg.linux-ha.org/agents/rev/612e2966f372
>>
>> I've had to commit a small revision, because on IA64, the memory on the
>> stack is not aligned properly for the cast to struct nd_neighbor_advert
>> * - http://hg.linux-ha.org/agents/rev/d206bc8f1303
>>
>> I apologize for the uglyness; it was the only way I could make gcc
>> shutup and get the alignment right. If someone can make the alignment
>> properly on the stack, I'm all ears ...
>
> You are right, that is a bit ugly.
> But I have no better ideas at this time :-(
How about this patch or along this line?
It assumes GCC but ICC should have a similar feature if you want to support it.
Alternatively, having an union with an u_int8_t array and a struct
should make an alignment correctly, I think.
--
Keisuke MORI
# HG changeset patch
# User Keisuke MORI <kskm...@intellilink.co.jp>
# Date 1281491442 -32400
# Node ID b12ca86af66197498cbf537ccc7ad4ff56cdf63b
# Parent d206bc8f13039b332e76a93a86e8e550b67781da
[mq]: ipv6addr-alignment.patch
diff -r d206bc8f1303 -r b12ca86af661 heartbeat/IPv6addr.c
--- a/heartbeat/IPv6addr.c Mon Aug 09 21:51:19 2010 +0200
+++ b/heartbeat/IPv6addr.c Wed Aug 11 10:50:42 2010 +0900
@@ -89,7 +89,6 @@
#include <stdio.h>
#include <stdlib.h>
-#include <malloc.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
@@ -424,10 +423,17 @@
int ifindex;
int hop;
struct ifreq ifr;
- u_int8_t *payload;
- int payload_size;
- struct nd_neighbor_advert *na;
- struct nd_opt_hdr *opt;
+
+ /* GCC is assumed.
+ * If you want to port to other than GCC, make sure that
+ * the packet is packed correctly.
+ */
+ struct neighbor_advert {
+ struct nd_neighbor_advert na;
+ struct nd_opt_hdr opt;
+ u_int8_t hwaddr[HWADDR_LEN];
+ } __attribute__ ((packed)) payload;
+
struct sockaddr_in6 src_sin6;
struct sockaddr_in6 dst_sin6;
@@ -473,39 +479,27 @@
}
/* build a neighbor advertisement message */
- payload_size = sizeof(struct nd_neighbor_advert)
- + sizeof(struct nd_opt_hdr) + HWADDR_LEN;
- payload = memalign(sysconf(_SC_PAGESIZE), payload_size);
- if (!payload) {
- cl_log(LOG_ERR, "malloc for payload failed");
- goto err;
- }
- memset(payload, 0, payload_size);
+ memset((void *)&payload, 0, sizeof(payload));
- /* Ugly typecast from ia64 hell! */
- na = (struct nd_neighbor_advert *)((void *)payload);
- na->nd_na_type = ND_NEIGHBOR_ADVERT;
- na->nd_na_code = 0;
- na->nd_na_cksum = 0; /* calculated by kernel */
- na->nd_na_flags_reserved = ND_NA_FLAG_OVERRIDE;
- na->nd_na_target = *src_ip;
+ payload.na.nd_na_type = ND_NEIGHBOR_ADVERT;
+ payload.na.nd_na_code = 0;
+ payload.na.nd_na_cksum = 0; /* calculated by kernel */
+ payload.na.nd_na_flags_reserved = ND_NA_FLAG_OVERRIDE;
+ payload.na.nd_na_target = *src_ip;
/* options field; set the target link-layer address */
- opt = (struct nd_opt_hdr *)(payload + sizeof(struct nd_neighbor_advert));
- opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
- opt->nd_opt_len = 1; /* The length of the option in units of 8 octets */
- memcpy(payload + sizeof(struct nd_neighbor_advert)
- + sizeof(struct nd_opt_hdr),
- &ifr.ifr_hwaddr.sa_data, HWADDR_LEN);
+ payload.opt.nd_opt_type = ND_OPT_TARGET_LINKADDR;
+ payload.opt.nd_opt_len = 1; /* The length of the option in units of 8 octets */
+ memcpy(payload.hwaddr, &ifr.ifr_hwaddr.sa_data, HWADDR_LEN);
/* sending an unsolicited neighbor advertisement to all */
memset(&dst_sin6, 0, sizeof(dst_sin6));
dst_sin6.sin6_family = AF_INET6;
inet_pton(AF_INET6, BCAST_ADDR, &dst_sin6.sin6_addr); /* should not fail */
- if (sendto(fd, payload, payload_size, 0,
+ if (sendto(fd, (void *)&payload, sizeof(payload), 0,
(struct sockaddr *)&dst_sin6, sizeof(dst_sin6))
- != payload_size) {
+ != sizeof(payload)) {
cl_log(LOG_ERR, "sendto(%s) failed: %s",
if_name, strerror(errno));
goto err;
@@ -515,7 +509,6 @@
err:
close(fd);
- free(payload);
return status;
}
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