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sd-dhcp: refactor dhcp_option_append 

Store a pointer to the options in the DHCPMessage struct, and pass
this together with an offset around, rather than a uint8_t**.

This avoids us having to (re)compute the pointer; and changes
dhcp_option_append from adjusting both the pointer to the next
option and the remaining size of the options, to just adjusting
the current offset.

This makes the code a bit simpler to follow IMHO, but there should
be no functional change.
This commit is contained in:
Tom Gundersen 2014-05-20 11:04:50 +02:00
parent ece6e766cf
commit 20b958bf15
6 changed files with 74 additions and 96 deletions
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6
src/libsystemd-network/dhcp-internal.h
View File

@ -36,8 +36,8 @@ int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
const void *packet, size_t len);
int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code,
size_t optlen, const void *optval);
int dhcp_option_append(uint8_t options[], size_t size, size_t *offset,
uint8_t code, size_t optlen, const void *optval);
typedef int (*dhcp_option_cb_t)(uint8_t code, uint8_t len,
const uint8_t *option, void *user_data);
@ -46,7 +46,7 @@ int dhcp_option_parse(DHCPMessage *message, size_t len,
dhcp_option_cb_t cb, void *user_data);
int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid, uint8_t type,
uint8_t **opt, size_t *optlen);
uint8_t options[], size_t optlen, size_t *optoffset);
uint16_t dhcp_packet_checksum(void *buf, size_t len);

33
src/libsystemd-network/dhcp-option.c
View File

@ -26,37 +26,33 @@
#include "dhcp-internal.h"
int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code,
size_t optlen, const void *optval)
{
if (!buf || !buflen)
return -EINVAL;
int dhcp_option_append(uint8_t options[], size_t size, size_t *offset,
uint8_t code, size_t optlen, const void *optval) {
assert(options);
assert(offset);
switch (code) {
case DHCP_OPTION_PAD:
case DHCP_OPTION_END:
if (*buflen < 1)
if (size - *offset < 1)
return -ENOBUFS;
(*buf)[0] = code;
*buf += 1;
*buflen -= 1;
options[*offset] = code;
*offset += 1;
break;
default:
if (*buflen < optlen + 2)
if (size - *offset < optlen + 2)
return -ENOBUFS;
if (!optval)
return -EINVAL;
assert(optval);
(*buf)[0] = code;
(*buf)[1] = optlen;
memcpy(&(*buf)[2], optval, optlen);
options[*offset] = code;
options[*offset + 1] = optlen;
memcpy(&options[*offset + 2], optval, optlen);
*buf += optlen + 2;
*buflen -= (optlen + 2);
*offset += optlen + 2;
break;
}
@ -143,7 +139,6 @@ int dhcp_option_parse(DHCPMessage *message, size_t len,
{
uint8_t overload = 0;
uint8_t message_type = 0;
uint8_t *opt = (uint8_t *)(message + 1);
int res;
if (!message)
@ -154,7 +149,7 @@ int dhcp_option_parse(DHCPMessage *message, size_t len,
len -= sizeof(DHCPMessage);
res = parse_options(opt, len, &overload, &message_type,
res = parse_options(message->options, len, &overload, &message_type,
cb, user_data);
if (res < 0)
return res;

15
src/libsystemd-network/dhcp-packet.c
View File

@ -38,8 +38,9 @@
#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
uint8_t type, uint8_t **opt, size_t *optlen) {
int err;
uint8_t type, uint8_t options[], size_t optlen, size_t *optoffset) {
size_t offset = 0;
int r;
assert(op == BOOTREQUEST || op == BOOTREPLY);
@ -49,12 +50,12 @@ int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
message->xid = htobe32(xid);
message->magic = htobe32(DHCP_MAGIC_COOKIE);
*opt = (uint8_t *)(message + 1);
r = dhcp_option_append(message->options, optlen, &offset,
DHCP_OPTION_MESSAGE_TYPE, 1, &type);
if (r < 0)
return r;
err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
&type);
if (err < 0)
return err;
*optoffset = offset;
return 0;
}

1
src/libsystemd-network/dhcp-protocol.h
View File

@ -44,6 +44,7 @@ struct DHCPMessage {
uint8_t sname[64];
uint8_t file[128];
be32_t magic;
uint8_t options[0];
} _packed_;
typedef struct DHCPMessage DHCPMessage;

57
src/libsystemd-network/sd-dhcp-client.c
View File

@ -257,19 +257,18 @@ static sd_dhcp_client *client_stop(sd_dhcp_client *client, int error) {
}
static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
uint8_t type, uint8_t **opt, size_t *optlen) {
uint8_t type, size_t optlen, size_t *optoffset) {
be16_t max_size;
int r;
assert(client);
assert(client->secs);
assert(message);
assert(opt);
assert(optlen);
assert(optoffset);
assert(type == DHCP_DISCOVER || type == DHCP_REQUEST);
r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
optlen);
r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
message->options, optlen, optoffset);
if (r < 0)
return r;
@ -285,7 +284,8 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
/* Some DHCP servers will refuse to issue an DHCP lease if the Client
Identifier option is not set */
r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
r = dhcp_option_append(message->options, optlen, optoffset,
DHCP_OPTION_CLIENT_IDENTIFIER,
sizeof(client->client_id), &client->client_id);
if (r < 0)
return r;
@ -299,10 +299,9 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
it MUST include that list in any subsequent DHCPREQUEST
messages.
*/
r = dhcp_option_append(opt, optlen,
r = dhcp_option_append(message->options, optlen, optoffset,
DHCP_OPTION_PARAMETER_REQUEST_LIST,
client->req_opts_size,
client->req_opts);
client->req_opts_size, client->req_opts);
if (r < 0)
return r;
@ -316,7 +315,7 @@ static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
*/
max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
DHCP_MIN_OPTIONS_SIZE);
r = dhcp_option_append(opt, optlen,
r = dhcp_option_append(message->options, optlen, optoffset,
DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
2, &max_size);
if (r < 0)
@ -336,8 +335,7 @@ static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
static int client_send_discover(sd_dhcp_client *client) {
_cleanup_free_ DHCPPacket *discover = NULL;
size_t optlen, len;
uint8_t *opt;
size_t optoffset, optlen, len;
usec_t time_now;
int r;
@ -364,7 +362,7 @@ static int client_send_discover(sd_dhcp_client *client) {
return -ENOMEM;
r = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
&opt, &optlen);
optlen, &optoffset);
if (r < 0)
return r;
@ -375,22 +373,21 @@ static int client_send_discover(sd_dhcp_client *client) {
option to suggest the lease time it would like.
*/
if (client->last_addr != INADDR_ANY) {
r = dhcp_option_append(&opt, &optlen,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
r = dhcp_option_append(discover->dhcp.options, optlen, &optoffset,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
return r;
}
r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
if (r < 0)
return r;
r = dhcp_option_append(discover->dhcp.options, optlen, &optoffset,
DHCP_OPTION_END, 0, NULL);
/* We currently ignore:
The client SHOULD wait a random time between one and ten seconds to
desynchronize the use of DHCP at startup.
*/
r = dhcp_client_send_raw(client, discover, len - optlen);
r = dhcp_client_send_raw(client, discover, sizeof(DHCPPacket) + optoffset);
if (r < 0)
return r;
@ -401,8 +398,7 @@ static int client_send_discover(sd_dhcp_client *client) {
static int client_send_request(sd_dhcp_client *client) {
_cleanup_free_ DHCPPacket *request;
size_t optlen, len;
uint8_t *opt;
size_t optoffset, optlen, len;
int r;
optlen = DHCP_MIN_OPTIONS_SIZE;
@ -412,8 +408,8 @@ static int client_send_request(sd_dhcp_client *client) {
if (!request)
return -ENOMEM;
r = client_message_init(client, &request->dhcp, DHCP_REQUEST, &opt,
&optlen);
r = client_message_init(client, &request->dhcp, DHCP_REQUEST,
optlen, &optoffset);
if (r < 0)
return r;
@ -428,13 +424,13 @@ static int client_send_request(sd_dhcp_client *client) {
filled in with the yiaddr value from the chosen DHCPOFFER.
*/
r = dhcp_option_append(&opt, &optlen,
r = dhcp_option_append(request->dhcp.options, optlen, &optoffset,
DHCP_OPTION_SERVER_IDENTIFIER,
4, &client->lease->server_address);
if (r < 0)
return r;
r = dhcp_option_append(&opt, &optlen,
r = dhcp_option_append(request->dhcp.options, optlen, &optoffset,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->lease->address);
if (r < 0)
@ -447,7 +443,7 @@ static int client_send_request(sd_dhcp_client *client) {
option MUST be filled in with client’s notion of its previously
assigned address. ’ciaddr’ MUST be zero.
*/
r = dhcp_option_append(&opt, &optlen,
r = dhcp_option_append(request->dhcp.options, optlen, &optoffset,
DHCP_OPTION_REQUESTED_IP_ADDRESS,
4, &client->last_addr);
if (r < 0)
@ -480,7 +476,8 @@ static int client_send_request(sd_dhcp_client *client) {
return -EINVAL;
}
r = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
r = dhcp_option_append(request->dhcp.options, optlen, &optoffset,
DHCP_OPTION_END, 0, NULL);
if (r < 0)
return r;
@ -489,9 +486,9 @@ static int client_send_request(sd_dhcp_client *client) {
client->lease->server_address,
DHCP_PORT_SERVER,
&request->dhcp,
len - optlen - DHCP_IP_UDP_SIZE);
sizeof(DHCPMessage) + optoffset);
} else {
r = dhcp_client_send_raw(client, request, len - optlen);
r = dhcp_client_send_raw(client, request, sizeof(DHCPPacket) + optoffset);
}
if (r < 0)
return r;

58
src/libsystemd-network/test-dhcp-option.c
View File

@ -85,16 +85,14 @@ static void test_invalid_buffer_length(void)
static void test_message_init(void)
{
_cleanup_free_ DHCPMessage *message = NULL;
size_t optlen = 3;
size_t optlen = 3, optoffset;
size_t len = sizeof(DHCPMessage) + optlen;
uint8_t *opt, *magic;
uint8_t *magic;
message = malloc0(len);
opt = (uint8_t *)(message + 1);
assert_se(dhcp_message_init(message, BOOTREQUEST, 0x12345678,
DHCP_DISCOVER, &opt, &optlen) >= 0);
DHCP_DISCOVER, message->options, optlen, &optoffset) >= 0);
assert_se(message->xid == htobe32(0x12345678));
assert_se(message->op == BOOTREQUEST);
@ -115,13 +113,11 @@ static DHCPMessage *create_message(uint8_t *options, uint16_t optlen,
{
DHCPMessage *message;
size_t len = sizeof(DHCPMessage) + optlen;
uint8_t *opt;
message = malloc0(len);
opt = (uint8_t *)(message + 1);
if (options && optlen)
memcpy(opt, options, optlen);
memcpy(&message->options, options, optlen);
if (file && filelen <= 128)
memcpy(&message->file, file, filelen);
@ -308,46 +304,34 @@ static uint8_t options[64] = {
static void test_option_set(void)
{
size_t len, oldlen;
int pos, i;
uint8_t *opt;
size_t offset = 0, len, pos;
unsigned i;
assert_se(dhcp_option_append(NULL, NULL, 0, 0, NULL) == -EINVAL);
len = 0;
opt = &result[0];
assert_se(dhcp_option_append(&opt, NULL, 0, 0, NULL) == -EINVAL);
assert_se(opt == &result[0] && len == 0);
assert_se(dhcp_option_append(&opt, &len, DHCP_OPTION_PAD,
assert_se(dhcp_option_append(result, 0, &offset, DHCP_OPTION_PAD,
0, NULL) == -ENOBUFS);
assert_se(opt == &result[0] && len == 0);
assert_se(offset == 0);
opt = &result[4];
len = 1;
assert_se(dhcp_option_append(&opt, &len, DHCP_OPTION_PAD,
offset = 4;
assert_se(dhcp_option_append(result, 1, &offset, DHCP_OPTION_PAD,
0, NULL) >= 0);
assert_se(opt == &result[5] && len == 0);
assert_se(offset == 5);
pos = 4;
offset = pos = 4;
len = 60;
while (pos < 64 && options[pos] != DHCP_OPTION_END) {
opt = &result[pos];
oldlen = len;
offset = pos;
assert_se(dhcp_option_append(&opt, &len, options[pos],
options[pos + 1],
&options[pos + 2]) >= 0);
assert_se(dhcp_option_append(result, len, &offset,
options[pos],
options[pos + 1],
&options[pos + 2]) >= 0);
if (options[pos] == DHCP_OPTION_PAD) {
assert_se(opt == &result[pos + 1]);
assert_se(len == oldlen - 1);
if (options[pos] == DHCP_OPTION_PAD)
pos++;
} else {
assert_se(opt == &result[pos + 2 + options[pos + 1]]);
assert_se(len == oldlen - 2 - options[pos + 1]);
else
pos += 2 + options[pos + 1];
}
assert_se(offset == pos);
}
for (i = 0; i < pos; i++) {