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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
networking/udhcp/common.c
View File

@ -404,14 +404,29 @@ void FAST_FUNC udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code,
#endif
/* Find option 'code' in opt_list */
struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code)
struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code, bool dhcpv6)
{
while (opt_list && opt_list->data[OPT_CODE] < code)
opt_list = opt_list->next;
IF_NOT_UDHCPC6(bool dhcpv6 = 0;)
uint8_t cur_code;
if (opt_list && opt_list->data[OPT_CODE] == code)
for (;;) {
if (!opt_list)
return opt_list; /* NULL */
if (!dhcpv6) {
cur_code = opt_list->data[OPT_CODE];
} else {
//FIXME: add support for code > 0xff
if (opt_list->data[D6_OPT_CODE] != 0)
return NULL;
cur_code = opt_list->data[D6_OPT_CODE + 1];
}
if (cur_code >= code) {
if (cur_code == code)
return opt_list;
return NULL;
}
opt_list = opt_list->next;
}
}
/* Parse string to IP in network order */
@ -499,7 +514,7 @@ static NOINLINE void attach_option(
}
#endif
existing = udhcp_find_option(*opt_list, optflag->code);
existing = udhcp_find_option(*opt_list, optflag->code, dhcpv6);
if (!existing) {
/* make a new option */
uint8_t *p = udhcp_insert_new_option(opt_list, optflag->code, length, dhcpv6);

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
//

5
networking/udhcp/d6_dhcpc.c
View File

@ -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,

6
networking/udhcp/dhcpc.c
View File

@ -658,7 +658,7 @@ static void add_client_options(struct dhcp_packet *packet)
// This will be needed if we remove -V VENDOR_STR in favor of
// -x vendor:VENDOR_STR
//if (!udhcp_find_option(packet.options, DHCP_VENDOR))
//if (!udhcp_find_option(packet.options, DHCP_VENDOR, /*dhcpv6:*/ 0))
// /* not set, set the default vendor ID */
// ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
}
@ -676,7 +676,7 @@ static void add_serverid_and_clientid_options(struct dhcp_packet *packet, uint32
* If the client used a 'client identifier' when it obtained the lease,
* it MUST use the same 'client identifier' in the DHCPRELEASE message.
*/
ci = udhcp_find_option(client_data.options, DHCP_CLIENT_ID);
ci = udhcp_find_option(client_data.options, DHCP_CLIENT_ID, /*dhcpv6:*/ 0);
if (ci)
udhcp_add_binary_option(packet, ci->data);
}
@ -1328,7 +1328,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
}
clientid_mac_ptr = NULL;
if (!(opt & OPT_C) && !udhcp_find_option(client_data.options, DHCP_CLIENT_ID)) {
if (!(opt & OPT_C) && !udhcp_find_option(client_data.options, DHCP_CLIENT_ID, /*dhcpv6:*/ 0)) {
/* not suppressed and not set, create default client ID */
clientid_mac_ptr = udhcp_insert_new_option(
&client_data.options, DHCP_CLIENT_ID,

2
networking/udhcp/dhcpd.c
View File

@ -935,7 +935,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
bb_simple_info_msg("started, v"BB_VER);
option = udhcp_find_option(server_data.options, DHCP_LEASE_TIME);
option = udhcp_find_option(server_data.options, DHCP_LEASE_TIME, /*dhcpv6:*/ 0);
server_data.max_lease_sec = DEFAULT_LEASE_TIME;
if (option) {
move_from_unaligned32(server_data.max_lease_sec, option->data + OPT_DATA);