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udhcpc6: fix udhcp_find_option to actually find DHCP6 options

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udhcp_insert_new_option treats code for IPv6 as follows:

new->data[D6_OPT_CODE] = code >> 8;
new->data[D6_OPT_CODE + 1] = code & 0xff;

udhcp_find_option tests the code as follows:

while (opt_list && opt_list->data[OPT_CODE] < code)
...
if (opt_list && opt_list->data[OPT_CODE] == code)

So yes, OPT_CODE and D6_OPT_CODE are both 0, but the D6_OPT_CLIENTID =
1 value means that the 1 is in the seconds byte, and udhcp_find_option
is only looking at the first byte,  So the send_d6_release can never
find it the created option.

function                                             old     new   delta
udhcp_find_option                                     28      53     +25
attach_option                                        276     284      +8
udhcpc6_main                                        2602    2607      +5
perform_d6_release                                   262     267      +5
udhcpd_main                                         1518    1520      +2
udhcpc_main                                         2542    2544      +2
add_serverid_and_clientid_options                     46      48      +2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 7/0 up/down: 49/0)               Total: 49 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2021-12-12 17:13:54 +01:00
parent 9b67880719
commit e67b80f473
5 changed files with 34 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
networking/udhcp/d6_dhcpc.c
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@@ -888,7 +888,8 @@ int send_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
if (client6_data.ia_pd)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, client6_data.ia_pd->len + 2+2);
/* Client-id */
ci = udhcp_find_option(client_data.options, D6_OPT_CLIENTID);
///vda
ci = udhcp_find_option(client_data.options, D6_OPT_CLIENTID, /*dhcpv6:*/ 1);
if (ci)
opt_ptr = mempcpy(opt_ptr, ci->data, D6_OPT_DATA + 2+2 + 6);
@@ -1272,7 +1273,7 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
}
clientid_mac_ptr = NULL;
if (!udhcp_find_option(client_data.options, D6_OPT_CLIENTID)) {
if (!udhcp_find_option(client_data.options, D6_OPT_CLIENTID, /*dhcpv6:*/ 1)) {
/* not set, set the default client ID */
clientid_mac_ptr = udhcp_insert_new_option(
&client_data.options, D6_OPT_CLIENTID,