[git commit] udhcpc[6]: do not pass xid around, keep it in client_data.xid
Denys Vlasenko
vda.linux at googlemail.com
Mon Jun 14 23:06:42 UTC 2021
commit: https://git.busybox.net/busybox/commit/?id=827b690fa7b9dd006f305449c342fb1b9bff6fb7
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
perform_release 105 169 +64
perform_d6_release 259 262 +3
init_d6_packet 84 85 +1
send_d6_discover 286 285 -1
send_d6_select 128 126 -2
send_d6_renew 176 174 -2
send_d6_info_request 65 63 -2
udhcpc_main 2555 2551 -4
send_select 130 122 -8
send_renew 99 91 -8
send_discover 89 81 -8
udhcpc6_main 2636 2602 -34
send_release 74 - -74
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 3/9 up/down: 68/-143) Total: -75 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
networking/udhcp/d6_dhcpc.c | 56 ++++++++++++++++++++++-----------------------
networking/udhcp/dhcpc.c | 51 +++++++++++++++--------------------------
networking/udhcp/dhcpc.h | 1 +
3 files changed, 48 insertions(+), 60 deletions(-)
diff --git a/networking/udhcp/d6_dhcpc.c b/networking/udhcp/d6_dhcpc.c
index 7f288f891..802a27521 100644
--- a/networking/udhcp/d6_dhcpc.c
+++ b/networking/udhcp/d6_dhcpc.c
@@ -479,15 +479,15 @@ static ALWAYS_INLINE uint32_t random_xid(void)
}
/* Initialize the packet with the proper defaults */
-static uint8_t *init_d6_packet(struct d6_packet *packet, char type, uint32_t xid)
+static uint8_t *init_d6_packet(struct d6_packet *packet, char type)
{
uint8_t *ptr;
unsigned secs;
memset(packet, 0, sizeof(*packet));
- packet->d6_xid32 = xid;
- packet->d6_msg_type = type;
+ packet->d6_xid32 = client_data.xid;
+ packet->d6_msg_type = type; /* union, overwrites lowest byte of d6_xid32 */
/* ELAPSED_TIME option is required to be present by the RFC,
* and some servers do check for its presense. [which?]
@@ -585,13 +585,13 @@ static int d6_mcast_from_client_data_ifindex(struct d6_packet *packet, uint8_t *
* about parameter values the client would like to have returned.
*/
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_d6_info_request(uint32_t xid)
+static NOINLINE int send_d6_info_request(void)
{
struct d6_packet packet;
uint8_t *opt_ptr;
- /* Fill in: msg type */
- opt_ptr = init_d6_packet(&packet, D6_MSG_INFORMATION_REQUEST, xid);
+ /* Fill in: msg type, xid, ELAPSED_TIME */
+ opt_ptr = init_d6_packet(&packet, D6_MSG_INFORMATION_REQUEST);
/* Add options: client-id,
* "param req" option according to -O, options specified with -x
@@ -684,14 +684,14 @@ static NOINLINE int send_d6_info_request(uint32_t xid)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ipv6)
+static NOINLINE int send_d6_discover(struct in6_addr *requested_ipv6)
{
struct d6_packet packet;
uint8_t *opt_ptr;
unsigned len;
- /* Fill in: msg type */
- opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT, xid);
+ /* Fill in: msg type, xid, ELAPSED_TIME */
+ opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT);
/* Create new IA_NA, optionally with included IAADDR with requested IP */
free(client6_data.ia_na);
@@ -763,13 +763,13 @@ static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ip
* messages from the server.
*/
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_d6_select(uint32_t xid)
+static NOINLINE int send_d6_select(void)
{
struct d6_packet packet;
uint8_t *opt_ptr;
- /* Fill in: msg type */
- opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST, xid);
+ /* Fill in: msg type, xid, ELAPSED_TIME */
+ opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST);
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
@@ -836,13 +836,13 @@ static NOINLINE int send_d6_select(uint32_t xid)
* about parameter values the client would like to have returned.
*/
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_d6_renew(uint32_t xid, struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
+static NOINLINE int send_d6_renew(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
{
struct d6_packet packet;
uint8_t *opt_ptr;
- /* Fill in: msg type */
- opt_ptr = init_d6_packet(&packet, DHCPREQUEST, xid);
+ /* Fill in: msg type, xid, ELAPSED_TIME */
+ opt_ptr = init_d6_packet(&packet, DHCPREQUEST);
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
@@ -877,8 +877,8 @@ int send_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
uint8_t *opt_ptr;
struct option_set *ci;
- /* Fill in: msg type, client id */
- opt_ptr = init_d6_packet(&packet, D6_MSG_RELEASE, random_xid());
+ /* Fill in: msg type, xid, ELAPSED_TIME */
+ opt_ptr = init_d6_packet(&packet, D6_MSG_RELEASE);
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
/* IA NA (contains our current IP) */
@@ -1097,6 +1097,7 @@ static void perform_d6_release(struct in6_addr *server_ipv6, struct in6_addr *ou
|| client_data.state == RENEW_REQUESTED
) {
bb_simple_info_msg("unicasting a release");
+ client_data.xid = random_xid(); //TODO: can omit?
send_d6_release(server_ipv6, our_cur_ipv6); /* unicast */
}
bb_simple_info_msg("entering released state");
@@ -1183,7 +1184,6 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
struct in6_addr srv6_buf;
struct in6_addr ipv6_buf;
struct in6_addr *requested_ipv6;
- uint32_t xid = 0;
int packet_num;
int timeout; /* must be signed */
int lease_remaining; /* must be signed */
@@ -1387,13 +1387,13 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
if (!discover_retries || packet_num < discover_retries) {
if (packet_num == 0) {
change_listen_mode(LISTEN_RAW);
- xid = random_xid();
+ client_data.xid = random_xid();
}
/* multicast */
if (opt & OPT_l)
- send_d6_info_request(xid);
+ send_d6_info_request();
else
- send_d6_discover(xid, requested_ipv6);
+ send_d6_discover(requested_ipv6);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1427,7 +1427,7 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
case REQUESTING:
if (!discover_retries || packet_num < discover_retries) {
/* send multicast select packet */
- send_d6_select(xid);
+ send_d6_select();
timeout = discover_timeout;
packet_num++;
continue;
@@ -1459,9 +1459,9 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
* into INIT_SELECTING state.
*/
if (opt & OPT_l)
- send_d6_info_request(xid);
+ send_d6_info_request();
else
- send_d6_renew(xid, &srv6_buf, requested_ipv6);
+ send_d6_renew(&srv6_buf, requested_ipv6);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1484,9 +1484,9 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
* try to find DHCP server using broadcast */
if (lease_remaining > 0 && packet_num < 3) {
if (opt & OPT_l)
- send_d6_info_request(xid);
+ send_d6_info_request();
else /* send a broadcast renew request */
- send_d6_renew(xid, /*server_ipv6:*/ NULL, requested_ipv6);
+ send_d6_renew(/*server_ipv6:*/ NULL, requested_ipv6);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1581,9 +1581,9 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
packet_end = (uint8_t*)&packet + len;
}
- if ((packet.d6_xid32 & htonl(0x00ffffff)) != xid) {
+ if ((packet.d6_xid32 & htonl(0x00ffffff)) != client_data.xid) {
log1("xid %x (our is %x)%s",
- (unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)xid,
+ (unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)client_data.xid,
", ignoring packet"
);
continue;
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index b80ea2f40..1c3c478ac 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -605,7 +605,7 @@ static void init_packet(struct dhcp_packet *packet, char type)
/* Fill in: op, htype, hlen, cookie fields; message type option: */
udhcp_init_header(packet, type);
- packet->xid = random_xid();
+ packet->xid = client_data.xid;
client_data.last_secs = monotonic_sec();
if (client_data.first_secs == 0)
@@ -719,17 +719,15 @@ static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t
/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
+static NOINLINE int send_discover(uint32_t requested)
{
struct dhcp_packet packet;
/* Fill in: op, htype, hlen, cookie, chaddr fields,
- * random xid field (we override it below),
- * message type option:
+ * xid field, message type option:
*/
init_packet(&packet, DHCPDISCOVER);
- packet.xid = xid;
if (requested)
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
@@ -747,7 +745,7 @@ static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
* "The client _broadcasts_ a DHCPREQUEST message..."
*/
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
+static NOINLINE int send_select(uint32_t server, uint32_t requested)
{
struct dhcp_packet packet;
struct in_addr temp_addr;
@@ -766,12 +764,10 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
* include that list in all subsequent messages.
*/
/* Fill in: op, htype, hlen, cookie, chaddr fields,
- * random xid field (we override it below),
- * message type option:
+ * xid field, message type option:
*/
init_packet(&packet, DHCPREQUEST);
- packet.xid = xid;
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
@@ -793,7 +789,7 @@ static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requeste
/* Unicast or broadcast a DHCP renew message */
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
+static NOINLINE int send_renew(uint32_t server, uint32_t ciaddr)
{
struct dhcp_packet packet;
@@ -812,12 +808,10 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
* replying to the client.
*/
/* Fill in: op, htype, hlen, cookie, chaddr fields,
- * random xid field (we override it below),
- * message type option:
+ * xid field, message type option:
*/
init_packet(&packet, DHCPREQUEST);
- packet.xid = xid;
packet.ciaddr = ciaddr;
/* Add options: maxsize,
@@ -839,7 +833,7 @@ static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
#if ENABLE_FEATURE_UDHCPC_ARPING
/* Broadcast a DHCP decline message */
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
+static NOINLINE int send_decline(uint32_t server, uint32_t requested)
{
struct dhcp_packet packet;
@@ -848,14 +842,6 @@ static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t req
*/
init_packet(&packet, DHCPDECLINE);
-#if 0
- /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
- * but in case the server is buggy and wants DHCPDECLINE's xid
- * to match the xid which started entire handshake,
- * we use the same xid we used in initial DHCPDISCOVER:
- */
- packet.xid = xid;
-#endif
/* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
@@ -1145,6 +1131,7 @@ static void perform_release(uint32_t server_addr, uint32_t requested_ip)
temp_addr.s_addr = requested_ip;
bb_info_msg("unicasting a release of %s to %s",
inet_ntoa(temp_addr), buffer);
+ client_data.xid = random_xid(); //TODO: can omit?
send_release(server_addr, requested_ip); /* unicast */
}
bb_simple_info_msg("entering released state");
@@ -1233,7 +1220,6 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
int discover_retries = 3;
uint32_t server_addr = server_addr; /* for compiler */
uint32_t requested_ip = 0;
- uint32_t xid = xid; /* for compiler */
int packet_num;
int timeout; /* must be signed */
int lease_remaining; /* must be signed */
@@ -1458,10 +1444,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
if (!discover_retries || packet_num < discover_retries) {
if (packet_num == 0) {
change_listen_mode(LISTEN_RAW);
- xid = random_xid();
+ client_data.xid = random_xid();
}
/* broadcast */
- send_discover(xid, requested_ip);
+ send_discover(requested_ip);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1495,7 +1481,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
case REQUESTING:
if (packet_num < 3) {
/* send broadcast select packet */
- send_select(xid, server_addr, requested_ip);
+ send_select(server_addr, requested_ip);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1526,7 +1512,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
* Anyway, it does recover by eventually failing through
* into INIT_SELECTING state.
*/
- if (send_renew(xid, server_addr, requested_ip) >= 0) {
+ if (send_renew(server_addr, requested_ip) >= 0) {
timeout = discover_timeout;
packet_num++;
continue;
@@ -1555,7 +1541,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
* try to find DHCP server using broadcast */
if (lease_remaining > 0 && packet_num < 3) {
/* send a broadcast renew request */
- send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
+ send_renew(0 /*INADDR_ANY*/, requested_ip);
timeout = discover_timeout;
packet_num++;
continue;
@@ -1648,9 +1634,9 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
continue;
}
- if (packet.xid != xid) {
+ if (packet.xid != client_data.xid) {
log1("xid %x (our is %x)%s",
- (unsigned)packet.xid, (unsigned)xid,
+ (unsigned)packet.xid, (unsigned)client_data.xid,
", ignoring packet"
);
continue;
@@ -1779,7 +1765,8 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
) {
bb_simple_info_msg("offered address is in use "
"(got ARP reply), declining");
- send_decline(/*xid,*/ server_addr, packet.yiaddr);
+ client_data.xid = random_xid(); //TODO: can omit?
+ send_decline(server_addr, packet.yiaddr);
if (client_data.state != REQUESTING)
d4_run_script_deconfig();
@@ -1814,7 +1801,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
timeout = (unsigned)lease_remaining / 2;
client_data.state = BOUND;
/* make future renew packets use different xid */
- /* xid = random_xid(); ...but why bother? */
+ /* client_data.xid = random_xid(); ...but why bother? */
packet_num = 0;
continue; /* back to main loop */
}
diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h
index cd9ead6bd..19b054b32 100644
--- a/networking/udhcp/dhcpc.h
+++ b/networking/udhcp/dhcpc.h
@@ -11,6 +11,7 @@ struct client_data_t {
uint8_t client_mac[6]; /* Our mac address */
IF_FEATURE_UDHCP_PORT(uint16_t port;)
int ifindex; /* Index number of the interface to use */
+ uint32_t xid;
uint8_t opt_mask[256 / 8]; /* Bitmask of options to send (-O option) */
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TODO: DHCPv6 has 16-bit option numbers
const char *interface; /* The name of the interface to use */
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