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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

6
networking/udhcp/common.h
View file

@ -245,7 +245,11 @@ void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t
char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
uint8_t *dname_enc(/*const uint8_t *cstr, int clen,*/ const char *src, int *retlen) FAST_FUNC;
#endif
struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
#if !ENABLE_UDHCPC6
#define udhcp_find_option(opt_list, code, dhcpv6) \
udhcp_find_option(opt_list, code)
#endif
struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code, bool dhcpv6) FAST_FUNC;
// RFC 2131 Table 5: Fields and options used by DHCP clients
//