From: Tom Gundersen Date: Tue, 20 May 2014 09:04:50 +0000 (+0200) Subject: sd-dhcp: refactor dhcp_option_append X-Git-Tag: v213~72 X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=20b958bf157dfb2f521b191ef7158035bcaa3003 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. --- diff --git a/src/libsystemd-network/dhcp-internal.h b/src/libsystemd-network/dhcp-internal.h index eb4a6cdce..56423a2cc 100644 --- a/src/libsystemd-network/dhcp-internal.h +++ b/src/libsystemd-network/dhcp-internal.h @@ -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); diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c index 1b92e8616..7bf881267 100644 --- a/src/libsystemd-network/dhcp-option.c +++ b/src/libsystemd-network/dhcp-option.c @@ -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; diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c index d72d7a686..10b645759 100644 --- a/src/libsystemd-network/dhcp-packet.c +++ b/src/libsystemd-network/dhcp-packet.c @@ -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; } diff --git a/src/libsystemd-network/dhcp-protocol.h b/src/libsystemd-network/dhcp-protocol.h index 539606cff..11de18629 100644 --- a/src/libsystemd-network/dhcp-protocol.h +++ b/src/libsystemd-network/dhcp-protocol.h @@ -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; diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 94235cf2f..cee4ccf78 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -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; diff --git a/src/libsystemd-network/test-dhcp-option.c b/src/libsystemd-network/test-dhcp-option.c index 35db8c1c0..eaf6a535e 100644 --- a/src/libsystemd-network/test-dhcp-option.c +++ b/src/libsystemd-network/test-dhcp-option.c @@ -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; - - 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); + size_t offset = 0, len, pos; + unsigned i; - 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++) {