[thirdparty/systemd.git] / src / libsystemd-network / dhcp-option.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
  Copyright © 2013 Intel Corporation. All rights reserved.
***/

#include <errno.h>
#include <stdint.h>
#include <stdio.h>

#include "alloc-util.h"
#include "dhcp-internal.h"
#include "dhcp-server-internal.h"
#include "memory-util.h"
#include "strv.h"
#include "utf8.h"

/* Append type-length value structure to the options buffer */
static int dhcp_option_append_tlv(uint8_t options[], size_t size, size_t *offset, uint8_t code, size_t optlen, const void *optval) {
        assert(options);
        assert(size > 0);
        assert(offset);
        assert(optlen <= UINT8_MAX);
        assert(*offset < size);

        if (*offset + 2 + optlen > size)
                return -ENOBUFS;

        options[*offset] = code;
        options[*offset + 1] = optlen;

        memcpy_safe(&options[*offset + 2], optval, optlen);
        *offset += 2 + optlen;
        return 0;
}

static int option_append(uint8_t options[], size_t size, size_t *offset,
                         uint8_t code, size_t optlen, const void *optval) {
        assert(options);
        assert(size > 0);
        assert(offset);

        int r;

        if (code != SD_DHCP_OPTION_END)
                /* always make sure there is space for an END option */
                size--;

        switch (code) {

        case SD_DHCP_OPTION_PAD:
        case SD_DHCP_OPTION_END:
                if (*offset + 1 > size)
                        return -ENOBUFS;

                options[*offset] = code;
                *offset += 1;
                break;

        case SD_DHCP_OPTION_USER_CLASS: {
                size_t total = 0;

                if (strv_isempty((char **) optval))
                        return -EINVAL;

                STRV_FOREACH(s, (const char* const*) optval) {
                        size_t len = strlen(*s);

                        if (len > 255 || len == 0)
                                return -EINVAL;

                        total += 1 + len;
                }

                if (*offset + 2 + total > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = total;
                *offset += 2;

                STRV_FOREACH(s, (const char* const*) optval) {
                        size_t len = strlen(*s);

                        options[*offset] = len;
                        memcpy(&options[*offset + 1], *s, len);
                        *offset += 1 + len;
                }

                break;
        }
        case SD_DHCP_OPTION_SIP_SERVER:
                if (*offset + 3 + optlen > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = optlen + 1;
                options[*offset + 2] = 1;

                memcpy_safe(&options[*offset + 3], optval, optlen);
                *offset += 3 + optlen;

                break;
        case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
                OrderedSet *s = (OrderedSet *) optval;
                struct sd_dhcp_option *p;
                size_t l = 0;

                ORDERED_SET_FOREACH(p, s)
                        l += p->length + 2;

                if (*offset + l + 2 > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = l;
                *offset += 2;

                ORDERED_SET_FOREACH(p, s) {
                        r = dhcp_option_append_tlv(options, size, offset, p->option, p->length, p->data);
                        if (r < 0)
                                return r;
                }
                break;
        }
        case SD_DHCP_OPTION_RELAY_AGENT_INFORMATION: {
                sd_dhcp_server *server = (sd_dhcp_server *) optval;
                size_t current_offset = *offset + 2;

                if (server->agent_circuit_id) {
                        r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_CIRCUIT_ID,
                                                   strlen(server->agent_circuit_id), server->agent_circuit_id);
                        if (r < 0)
                                return r;
                }
                if (server->agent_remote_id) {
                        r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_REMOTE_ID,
                                                   strlen(server->agent_remote_id), server->agent_remote_id);
                        if (r < 0)
                                return r;
                }

                options[*offset] = code;
                options[*offset + 1] = current_offset - *offset - 2;
                assert(current_offset - *offset - 2 <= UINT8_MAX);
                *offset = current_offset;
                break;
        }
        default:
                return dhcp_option_append_tlv(options, size, offset, code, optlen, optval);
        }
        return 0;
}

static int option_length(uint8_t *options, size_t length, size_t offset) {
        assert(options);
        assert(offset < length);

        if (IN_SET(options[offset], SD_DHCP_OPTION_PAD, SD_DHCP_OPTION_END))
                return 1;
        if (length < offset + 2)
                return -ENOBUFS;

        /* validating that buffer is long enough */
        if (length < offset + 2 + options[offset + 1])
                return -ENOBUFS;

        return options[offset + 1] + 2;
}

int dhcp_option_find_option(uint8_t *options, size_t length, uint8_t code, size_t *ret_offset) {
        int r;

        assert(options);
        assert(ret_offset);

        for (size_t offset = 0; offset < length; offset += r) {
                r = option_length(options, length, offset);
                if (r < 0)
                        return r;

                if (code == options[offset]) {
                        *ret_offset = offset;
                        return r;
                }
        }
        return -ENOENT;
}

int dhcp_option_remove_option(uint8_t *options, size_t length, uint8_t option_code) {
        int r;
        size_t offset;

        assert(options);

        r = dhcp_option_find_option(options, length, option_code, &offset);
        if (r < 0)
                return r;

        memmove(options + offset, options + offset + r, length - offset - r);
        return length - r;
}

int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset,
                       uint8_t overload,
                       uint8_t code, size_t optlen, const void *optval) {
        const bool use_file = overload & DHCP_OVERLOAD_FILE;
        const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
        int r;

        assert(message);
        assert(offset);

        /* If *offset is in range [0, size), we are writing to ->options,
         * if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
         * if *offset is in range [size + use_file*sizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
         * and use_sname, we are writing to ->sname.
         */

        if (*offset < size) {
                /* still space in the options array */
                r = option_append(message->options, size, offset, code, optlen, optval);
                if (r >= 0)
                        return 0;
                else if (r == -ENOBUFS && (use_file || use_sname)) {
                        /* did not fit, but we have more buffers to try
                           close the options array and move the offset to its end */
                        r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
                        if (r < 0)
                                return r;

                        *offset = size;
                } else
                        return r;
        }

        if (use_file) {
                size_t file_offset = *offset - size;

                if (file_offset < sizeof(message->file)) {
                        /* still space in the 'file' array */
                        r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
                        if (r >= 0) {
                                *offset = size + file_offset;
                                return 0;
                        } else if (r == -ENOBUFS && use_sname) {
                                /* did not fit, but we have more buffers to try
                                   close the file array and move the offset to its end */
                                r = option_append(message->file, sizeof(message->file), &file_offset, SD_DHCP_OPTION_END, 0, NULL);
                                if (r < 0)
                                        return r;

                                *offset = size + sizeof(message->file);
                        } else
                                return r;
                }
        }

        if (use_sname) {
                size_t sname_offset = *offset - size - use_file*sizeof(message->file);

                if (sname_offset < sizeof(message->sname)) {
                        /* still space in the 'sname' array */
                        r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
                        if (r >= 0) {
                                *offset = size + use_file*sizeof(message->file) + sname_offset;
                                return 0;
                        } else
                                /* no space, or other error, give up */
                                return r;
                }
        }

        return -ENOBUFS;
}

static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
                         uint8_t *message_type, char **error_message, dhcp_option_callback_t cb,
                         void *userdata) {
        uint8_t code, len;
        const uint8_t *option;
        size_t offset = 0;
        int r;

        while (offset < buflen) {
                code = options[offset ++];

                switch (code) {
                case SD_DHCP_OPTION_PAD:
                        continue;

                case SD_DHCP_OPTION_END:
                        return 0;
                }

                if (buflen < offset + 1)
                        return -ENOBUFS;

                len = options[offset ++];

                if (buflen < offset + len)
                        return -EINVAL;

                option = &options[offset];

                switch (code) {
                case SD_DHCP_OPTION_MESSAGE_TYPE:
                        if (len != 1)
                                return -EINVAL;

                        if (message_type)
                                *message_type = *option;

                        break;

                case SD_DHCP_OPTION_ERROR_MESSAGE:
                        if (len == 0)
                                return -EINVAL;

                        if (error_message) {
                                _cleanup_free_ char *string = NULL;

                                r = make_cstring((const char*) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
                                if (r < 0)
                                        return r;

                                if (!ascii_is_valid(string))
                                        return -EINVAL;

                                free_and_replace(*error_message, string);
                        }

                        break;
                case SD_DHCP_OPTION_OVERLOAD:
                        if (len != 1)
                                return -EINVAL;

                        if (overload)
                                *overload = *option;

                        break;

                default:
                        if (cb)
                                cb(code, len, option, userdata);

                        break;
                }

                offset += len;
        }

        if (offset < buflen)
                return -EINVAL;

        return 0;
}

int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **ret_error_message) {
        _cleanup_free_ char *error_message = NULL;
        uint8_t overload = 0;
        uint8_t message_type = 0;
        int r;

        if (!message)
                return -EINVAL;

        if (len < sizeof(DHCPMessage))
                return -EINVAL;

        len -= sizeof(DHCPMessage);

        r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
        if (r < 0)
                return r;

        if (overload & DHCP_OVERLOAD_FILE) {
                r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
                if (r < 0)
                        return r;
        }

        if (overload & DHCP_OVERLOAD_SNAME) {
                r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
                if (r < 0)
                        return r;
        }

        if (message_type == 0)
                return -ENOMSG;

        if (ret_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
                *ret_error_message = TAKE_PTR(error_message);

        return message_type;
}

int dhcp_option_parse_string(const uint8_t *option, size_t len, char **ret) {
        int r;

        assert(option);
        assert(ret);

        if (len <= 0)
                *ret = mfree(*ret);
        else {
                char *string;

                /*
                 * One trailing NUL byte is OK, we don't mind. See:
                 * https://github.com/systemd/systemd/issues/1337
                 */
                r = make_cstring((const char *) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
                if (r < 0)
                        return r;

                free_and_replace(*ret, string);
        }

        return 0;
}

static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
        if (!i)
                return NULL;

        free(i->data);
        return mfree(i);
}

int sd_dhcp_option_new(uint8_t option, const void *data, size_t length, sd_dhcp_option **ret) {
        assert_return(ret, -EINVAL);
        assert_return(length == 0 || data, -EINVAL);

        _cleanup_free_ void *q = memdup(data, length);
        if (!q)
                return -ENOMEM;

        sd_dhcp_option *p = new(sd_dhcp_option, 1);
        if (!p)
                return -ENOMEM;

        *p = (sd_dhcp_option) {
                .n_ref = 1,
                .option = option,
                .length = length,
                .data = TAKE_PTR(q),
        };

        *ret = TAKE_PTR(p);
        return 0;
}

DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                dhcp_option_hash_ops,
                void,
                trivial_hash_func,
                trivial_compare_func,
                sd_dhcp_option,
                sd_dhcp_option_unref);
Commit	Line	Data
db9ecf05	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
524cf458	2	/***
810adae9	3	Copyright © 2013 Intel Corporation. All rights reserved.
524cf458 PF	4	***/
524cf458 PF	5
524cf458	6	#include <errno.h>
cf0fbc49	7	#include <stdint.h>
524cf458 PF	8	#include <stdio.h>
524cf458 PF	9
f693e9b3	10	#include "alloc-util.h"
524cf458	11	#include "dhcp-internal.h"
564ca984	12	#include "dhcp-server-internal.h"
0a970718 LP	13	#include "memory-util.h"
	14	#include "strv.h"
	15	#include "utf8.h"
524cf458	16
11c38d3e YA	17	/* Append type-length value structure to the options buffer */
	18	static int dhcp_option_append_tlv(uint8_t options[], size_t size, size_t offset, uint8_t code, size_t optlen, const void optval) {
	19	assert(options);
	20	assert(size > 0);
	21	assert(offset);
	22	assert(optlen <= UINT8_MAX);
	23	assert(*offset < size);
	24
	25	if (*offset + 2 + optlen > size)
	26	return -ENOBUFS;
	27
	28	options[*offset] = code;
	29	options[*offset + 1] = optlen;
	30
	31	memcpy_safe(&options[*offset + 2], optval, optlen);
	32	*offset += 2 + optlen;
	33	return 0;
	34	}
	35
04b28be1 TG	36	static int option_append(uint8_t options[], size_t size, size_t *offset,
04b28be1 TG	37	uint8_t code, size_t optlen, const void *optval) {
20b958bf	38	assert(options);
828b603a	39	assert(size > 0);
20b958bf	40	assert(offset);
524cf458	41
11c38d3e YA	42	int r;
11c38d3e YA	43
22805d92	44	if (code != SD_DHCP_OPTION_END)
2688ef60	45	/* always make sure there is space for an END option */
313cefa1	46	size--;
2688ef60	47
524cf458 PF	48	switch (code) {
524cf458 PF	49
22805d92 BG	50	case SD_DHCP_OPTION_PAD:
22805d92 BG	51	case SD_DHCP_OPTION_END:
bc67342e	52	if (*offset + 1 > size)
524cf458 PF	53	return -ENOBUFS;
524cf458 PF	54
20b958bf TG	55	options[*offset] = code;
20b958bf TG	56	*offset += 1;
524cf458 PF	57	break;
524cf458 PF	58
af1c0de0	59	case SD_DHCP_OPTION_USER_CLASS: {
bc67342e	60	size_t total = 0;
af1c0de0	61
e4336c0a YW	62	if (strv_isempty((char **) optval))
	63	return -EINVAL;
	64
c9c3b81f	65	STRV_FOREACH(s, (const char* const*) optval) {
bc67342e ZJS	66	size_t len = strlen(*s);
bc67342e ZJS	67
e4336c0a YW	68	if (len > 255 \|\| len == 0)
e4336c0a YW	69	return -EINVAL;
bc67342e ZJS	70
	71	total += 1 + len;
	72	}
af1c0de0	73
bc67342e	74	if (*offset + 2 + total > size)
af1c0de0 SS	75	return -ENOBUFS;
	76
	77	options[*offset] = code;
e4336c0a	78	options[*offset + 1] = total;
af1c0de0 SS	79	*offset += 2;
af1c0de0 SS	80
c9c3b81f	81	STRV_FOREACH(s, (const char* const*) optval) {
bc67342e	82	size_t len = strlen(*s);
af1c0de0 SS	83
af1c0de0 SS	84	options[*offset] = len;
bc67342e ZJS	85	memcpy(&options[offset + 1], s, len);
bc67342e ZJS	86	*offset += 1 + len;
af1c0de0 SS	87	}
	88
	89	break;
	90	}
299d578f SS	91	case SD_DHCP_OPTION_SIP_SERVER:
	92	if (*offset + 3 + optlen > size)
	93	return -ENOBUFS;
	94
	95	options[*offset] = code;
	96	options[*offset + 1] = optlen + 1;
	97	options[*offset + 2] = 1;
	98
	99	memcpy_safe(&options[*offset + 3], optval, optlen);
	100	*offset += 3 + optlen;
	101
	102	break;
564ca984	103	case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
ebffea2a	104	OrderedSet s = (OrderedSet ) optval;
461dbb2f	105	struct sd_dhcp_option *p;
564ca984	106	size_t l = 0;
564ca984	107
ebffea2a	108	ORDERED_SET_FOREACH(p, s)
564ca984 SS	109	l += p->length + 2;
	110
	111	if (*offset + l + 2 > size)
	112	return -ENOBUFS;
	113
	114	options[*offset] = code;
	115	options[*offset + 1] = l;
564ca984 SS	116	*offset += 2;
564ca984 SS	117
ebffea2a	118	ORDERED_SET_FOREACH(p, s) {
11c38d3e YA	119	r = dhcp_option_append_tlv(options, size, offset, p->option, p->length, p->data);
	120	if (r < 0)
	121	return r;
	122	}
	123	break;
	124	}
	125	case SD_DHCP_OPTION_RELAY_AGENT_INFORMATION: {
	126	sd_dhcp_server server = (sd_dhcp_server ) optval;
	127	size_t current_offset = *offset + 2;
	128
	129	if (server->agent_circuit_id) {
	130	r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_CIRCUIT_ID,
	131	strlen(server->agent_circuit_id), server->agent_circuit_id);
	132	if (r < 0)
	133	return r;
	134	}
	135	if (server->agent_remote_id) {
	136	r = dhcp_option_append_tlv(options, size, &current_offset, SD_DHCP_RELAY_AGENT_REMOTE_ID,
	137	strlen(server->agent_remote_id), server->agent_remote_id);
	138	if (r < 0)
	139	return r;
564ca984 SS	140	}
564ca984 SS	141
11c38d3e YA	142	options[*offset] = code;
	143	options[offset + 1] = current_offset - offset - 2;
	144	assert(current_offset - *offset - 2 <= UINT8_MAX);
	145	*offset = current_offset;
564ca984 SS	146	break;
564ca984 SS	147	}
524cf458	148	default:
11c38d3e YA	149	return dhcp_option_append_tlv(options, size, offset, code, optlen, optval);
	150	}
	151	return 0;
	152	}
524cf458	153
11c38d3e YA	154	static int option_length(uint8_t *options, size_t length, size_t offset) {
	155	assert(options);
	156	assert(offset < length);
04b28be1	157
11c38d3e YA	158	if (IN_SET(options[offset], SD_DHCP_OPTION_PAD, SD_DHCP_OPTION_END))
	159	return 1;
	160	if (length < offset + 2)
	161	return -ENOBUFS;
524cf458	162
11c38d3e YA	163	/* validating that buffer is long enough */
	164	if (length < offset + 2 + options[offset + 1])
	165	return -ENOBUFS;
	166
	167	return options[offset + 1] + 2;
	168	}
	169
	170	int dhcp_option_find_option(uint8_t options, size_t length, uint8_t code, size_t ret_offset) {
	171	int r;
	172
	173	assert(options);
	174	assert(ret_offset);
	175
	176	for (size_t offset = 0; offset < length; offset += r) {
	177	r = option_length(options, length, offset);
	178	if (r < 0)
	179	return r;
	180
	181	if (code == options[offset]) {
	182	*ret_offset = offset;
	183	return r;
	184	}
524cf458	185	}
11c38d3e YA	186	return -ENOENT;
11c38d3e YA	187	}
524cf458	188
11c38d3e YA	189	int dhcp_option_remove_option(uint8_t *options, size_t length, uint8_t option_code) {
	190	int r;
	191	size_t offset;
	192
	193	assert(options);
	194
	195	r = dhcp_option_find_option(options, length, option_code, &offset);
	196	if (r < 0)
	197	return r;
	198
	199	memmove(options + offset, options + offset + r, length - offset - r);
	200	return length - r;
524cf458 PF	201	}
524cf458 PF	202
04b28be1 TG	203	int dhcp_option_append(DHCPMessage message, size_t size, size_t offset,
	204	uint8_t overload,
	205	uint8_t code, size_t optlen, const void *optval) {
bc67342e ZJS	206	const bool use_file = overload & DHCP_OVERLOAD_FILE;
bc67342e ZJS	207	const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
04b28be1 TG	208	int r;
	209
	210	assert(message);
	211	assert(offset);
	212
bc67342e ZJS	213	/* If *offset is in range [0, size), we are writing to ->options,
	214	* if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
	215	* if offset is in range [size + use_filesizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
	216	* and use_sname, we are writing to ->sname.
	217	*/
04b28be1 TG	218
	219	if (*offset < size) {
	220	/* still space in the options array */
	221	r = option_append(message->options, size, offset, code, optlen, optval);
	222	if (r >= 0)
	223	return 0;
bc67342e	224	else if (r == -ENOBUFS && (use_file \|\| use_sname)) {
04b28be1 TG	225	/* did not fit, but we have more buffers to try
04b28be1 TG	226	close the options array and move the offset to its end */
22805d92	227	r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	228	if (r < 0)
	229	return r;
	230
	231	*offset = size;
	232	} else
	233	return r;
	234	}
	235
bc67342e ZJS	236	if (use_file) {
bc67342e ZJS	237	size_t file_offset = *offset - size;
04b28be1 TG	238
	239	if (file_offset < sizeof(message->file)) {
	240	/* still space in the 'file' array */
	241	r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
	242	if (r >= 0) {
	243	*offset = size + file_offset;
	244	return 0;
bc67342e	245	} else if (r == -ENOBUFS && use_sname) {
04b28be1 TG	246	/* did not fit, but we have more buffers to try
04b28be1 TG	247	close the file array and move the offset to its end */
828b603a	248	r = option_append(message->file, sizeof(message->file), &file_offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	249	if (r < 0)
	250	return r;
	251
	252	*offset = size + sizeof(message->file);
	253	} else
	254	return r;
	255	}
	256	}
	257
bc67342e ZJS	258	if (use_sname) {
bc67342e ZJS	259	size_t sname_offset = offset - size - use_filesizeof(message->file);
04b28be1 TG	260
	261	if (sname_offset < sizeof(message->sname)) {
	262	/* still space in the 'sname' array */
	263	r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
	264	if (r >= 0) {
bc67342e	265	offset = size + use_filesizeof(message->file) + sname_offset;
04b28be1	266	return 0;
bc67342e	267	} else
04b28be1 TG	268	/* no space, or other error, give up */
04b28be1 TG	269	return r;
04b28be1 TG	270	}
	271	}
	272
	273	return -ENOBUFS;
	274	}
	275
32008a96	276	static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
ccf86354	277	uint8_t message_type, char *error_message, dhcp_option_callback_t cb,
89ca10c6	278	void *userdata) {
32008a96	279	uint8_t code, len;
f693e9b3	280	const uint8_t *option;
32008a96	281	size_t offset = 0;
7153213e	282	int r;
524cf458	283
32008a96	284	while (offset < buflen) {
f693e9b3	285	code = options[offset ++];
32008a96	286
f693e9b3	287	switch (code) {
22805d92	288	case SD_DHCP_OPTION_PAD:
f693e9b3	289	continue;
524cf458	290
22805d92	291	case SD_DHCP_OPTION_END:
524cf458	292	return 0;
f693e9b3	293	}
524cf458	294
f693e9b3 TG	295	if (buflen < offset + 1)
	296	return -ENOBUFS;
	297
	298	len = options[offset ++];
524cf458	299
f693e9b3 TG	300	if (buflen < offset + len)
	301	return -EINVAL;
	302
	303	option = &options[offset];
	304
	305	switch (code) {
22805d92	306	case SD_DHCP_OPTION_MESSAGE_TYPE:
32008a96	307	if (len != 1)
524cf458 PF	308	return -EINVAL;
	309
	310	if (message_type)
f693e9b3	311	message_type = option;
524cf458 PF	312
	313	break;
	314
22805d92	315	case SD_DHCP_OPTION_ERROR_MESSAGE:
f693e9b3	316	if (len == 0)
524cf458 PF	317	return -EINVAL;
524cf458 PF	318
f693e9b3 TG	319	if (error_message) {
f693e9b3 TG	320	_cleanup_free_ char *string = NULL;
524cf458	321
7153213e LP	322	r = make_cstring((const char*) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
	323	if (r < 0)
	324	return r;
524cf458	325
f693e9b3 TG	326	if (!ascii_is_valid(string))
f693e9b3 TG	327	return -EINVAL;
524cf458	328
f9ecfd3b	329	free_and_replace(*error_message, string);
f693e9b3	330	}
524cf458	331
f693e9b3	332	break;
22805d92	333	case SD_DHCP_OPTION_OVERLOAD:
f693e9b3	334	if (len != 1)
524cf458	335	return -EINVAL;
524cf458	336
f693e9b3 TG	337	if (overload)
f693e9b3 TG	338	overload = option;
524cf458	339
f693e9b3 TG	340	break;
	341
	342	default:
	343	if (cb)
	344	cb(code, len, option, userdata);
524cf458 PF	345
	346	break;
	347	}
f693e9b3 TG	348
f693e9b3 TG	349	offset += len;
524cf458 PF	350	}
524cf458 PF	351
32008a96	352	if (offset < buflen)
524cf458 PF	353	return -EINVAL;
	354
	355	return 0;
	356	}
	357
7b1fac1e	358	int dhcp_option_parse(DHCPMessage message, size_t len, dhcp_option_callback_t cb, void userdata, char **ret_error_message) {
f693e9b3	359	_cleanup_free_ char *error_message = NULL;
524cf458 PF	360	uint8_t overload = 0;
524cf458 PF	361	uint8_t message_type = 0;
32008a96	362	int r;
524cf458 PF	363
	364	if (!message)
	365	return -EINVAL;
	366
3b7ca119	367	if (len < sizeof(DHCPMessage))
524cf458 PF	368	return -EINVAL;
524cf458 PF	369
3b7ca119	370	len -= sizeof(DHCPMessage);
524cf458	371
f693e9b3	372	r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
32008a96 TG	373	if (r < 0)
32008a96 TG	374	return r;
524cf458 PF	375
524cf458 PF	376	if (overload & DHCP_OVERLOAD_FILE) {
f693e9b3	377	r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	378	if (r < 0)
32008a96 TG	379	return r;
524cf458 PF	380	}
	381
	382	if (overload & DHCP_OVERLOAD_SNAME) {
f693e9b3	383	r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	384	if (r < 0)
32008a96 TG	385	return r;
524cf458 PF	386	}
524cf458 PF	387
f693e9b3 TG	388	if (message_type == 0)
	389	return -ENOMSG;
	390
7b1fac1e YW	391	if (ret_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
7b1fac1e YW	392	*ret_error_message = TAKE_PTR(error_message);
524cf458	393
f693e9b3	394	return message_type;
524cf458	395	}
461dbb2f	396
930133d5 RH	397	int dhcp_option_parse_string(const uint8_t option, size_t len, char *ret) {
	398	int r;
	399
	400	assert(option);
	401	assert(ret);
	402
	403	if (len <= 0)
	404	ret = mfree(ret);
	405	else {
	406	char *string;
	407
	408	/*
	409	* One trailing NUL byte is OK, we don't mind. See:
	410	* https://github.com/systemd/systemd/issues/1337
	411	*/
	412	r = make_cstring((const char *) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
	413	if (r < 0)
	414	return r;
	415
	416	free_and_replace(*ret, string);
	417	}
	418
	419	return 0;
	420	}
	421
461dbb2f YW	422	static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
	423	if (!i)
	424	return NULL;
	425
	426	free(i->data);
	427	return mfree(i);
	428	}
	429
	430	int sd_dhcp_option_new(uint8_t option, const void data, size_t length, sd_dhcp_option *ret) {
	431	assert_return(ret, -EINVAL);
	432	assert_return(length == 0 \|\| data, -EINVAL);
	433
	434	_cleanup_free_ void *q = memdup(data, length);
	435	if (!q)
	436	return -ENOMEM;
	437
	438	sd_dhcp_option *p = new(sd_dhcp_option, 1);
	439	if (!p)
	440	return -ENOMEM;
	441
	442	*p = (sd_dhcp_option) {
	443	.n_ref = 1,
	444	.option = option,
	445	.length = length,
	446	.data = TAKE_PTR(q),
	447	};
	448
	449	*ret = TAKE_PTR(p);
	450	return 0;
	451	}
	452
	453	DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
	454	DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
	455	dhcp_option_hash_ops,
	456	void,
	457	trivial_hash_func,
	458	trivial_compare_func,
	459	sd_dhcp_option,
	460	sd_dhcp_option_unref);