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udhcpd: don't fail ARP check if returned MAC matches client's one

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Also, do not unicast replies to yiaddr.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2009-06-16 10:20:27 +02:00
parent 1f363a0867
commit 47f2d7ef7d
6 changed files with 67 additions and 34 deletions
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21
networking/udhcp/arpping.c
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@@ -41,7 +41,11 @@ enum {
/* Returns 1 if no reply received */
int FAST_FUNC arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *interface)
int FAST_FUNC arpping(uint32_t test_ip,
const uint8_t *safe_mac,
uint32_t from_ip,
uint8_t *from_mac,
const char *interface)
{
int timeout_ms;
struct pollfd pfd[1];
@@ -73,7 +77,7 @@ int FAST_FUNC arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, con
arp.operation = htons(ARPOP_REQUEST); /* ARP op code */
memcpy(arp.sHaddr, from_mac, 6); /* source hardware address */
memcpy(arp.sInaddr, &from_ip, sizeof(from_ip)); /* source IP address */
/* tHaddr is zero-fiiled */ /* target hardware address */
/* tHaddr is zero-filled */ /* target hardware address */
memcpy(arp.tInaddr, &test_ip, sizeof(test_ip)); /* target IP address */
memset(&addr, 0, sizeof(addr));
@@ -98,13 +102,24 @@ int FAST_FUNC arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, con
r = read(s, &arp, sizeof(arp));
if (r < 0)
break;
//bb_error_msg("sHaddr %02x:%02x:%02x:%02x:%02x:%02x",
// arp.sHaddr[0], arp.sHaddr[1], arp.sHaddr[2],
// arp.sHaddr[3], arp.sHaddr[4], arp.sHaddr[5]);
if (r >= ARP_MSG_SIZE
&& arp.operation == htons(ARPOP_REPLY)
/* don't check it: Linux doesn't return proper tHaddr (fixed in 2.6.24?) */
/* && memcmp(arp.tHaddr, from_mac, 6) == 0 */
&& *((uint32_t *) arp.sInaddr) == test_ip
) {
rv = 0;
/* if ARP source MAC matches safe_mac
* (which is client's MAC), then it's not a conflict
* (client simply already has this IP and replies to ARPs!)
*/
if (!safe_mac || memcmp(safe_mac, arp.sHaddr, 6) != 0)
rv = 0;
//else bb_error_msg("sHaddr == safe_mac");
break;
}
}