1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* NOTICE: This is a clean room re-implementation of libnl */ 18 19#include <errno.h> 20#include "netlink/netlink.h" 21#include "netlink/msg.h" 22#include "netlink/attr.h" 23#include "netlink-types.h" 24 25/* Return payload of string attribute. */ 26char *nla_get_string(struct nlattr *nla) 27{ 28 return (char *) nla_data(nla); 29} 30 31/* Return payload of 16 bit integer attribute. */ 32uint16_t nla_get_u16(struct nlattr *nla) 33{ 34 return *((uint16_t *) nla_data(nla)); 35} 36 37/* Return payload of 32 bit integer attribute. */ 38uint32_t nla_get_u32(struct nlattr *nla) 39{ 40 return *((uint32_t *) nla_data(nla)); 41} 42 43/* Return value of 8 bit integer attribute. */ 44uint8_t nla_get_u8(struct nlattr *nla) 45{ 46 return *((uint8_t *) nla_data(nla)); 47} 48 49/* Return payload of uint64_t attribute. */ 50uint64_t nla_get_u64(struct nlattr *nla) 51{ 52 uint64_t tmp; 53 nla_memcpy(&tmp, nla, sizeof(tmp)); 54 return tmp; 55} 56 57/* Head of payload */ 58void *nla_data(const struct nlattr *nla) 59{ 60 return (void *) ((char *) nla + NLA_HDRLEN); 61} 62 63/* Return length of the payload . */ 64int nla_len(const struct nlattr *nla) 65{ 66 return nla->nla_len - NLA_HDRLEN; 67} 68 69int nla_padlen(int payload) 70{ 71 return NLA_ALIGN(payload) - payload; 72} 73 74/* Start a new level of nested attributes. */ 75struct nlattr *nla_nest_start(struct nl_msg *msg, int attrtype) 76{ 77 struct nlattr *start = (struct nlattr *)nlmsg_tail(msg->nm_nlh); 78 int rc; 79 80 rc = nla_put(msg, attrtype, 0, NULL); 81 if (rc < 0) 82 return NULL; 83 84 return start; 85} 86 87/* Finalize nesting of attributes. */ 88int nla_nest_end(struct nl_msg *msg, struct nlattr *start) 89{ 90 /* Set attribute size */ 91 start->nla_len = (unsigned char *)nlmsg_tail(nlmsg_hdr(msg)) - 92 (unsigned char *)start; 93 return 0; 94} 95 96/* Return next attribute in a stream of attributes. */ 97struct nlattr *nla_next(const struct nlattr *nla, int *remaining) 98{ 99 struct nlattr *next_nla = NULL; 100 if (nla->nla_len >= sizeof(struct nlattr) && 101 nla->nla_len <= *remaining){ 102 next_nla = (struct nlattr *) \ 103 ((char *) nla + NLA_ALIGN(nla->nla_len)); 104 *remaining = *remaining - NLA_ALIGN(nla->nla_len); 105 } 106 107 return next_nla; 108 109} 110 111/* Check if the attribute header and payload can be accessed safely. */ 112int nla_ok(const struct nlattr *nla, int remaining) 113{ 114 return remaining > 0 && 115 nla->nla_len >= sizeof(struct nlattr) && 116 sizeof(struct nlattr) <= (unsigned int) remaining && 117 nla->nla_len <= remaining; 118} 119 120/* Create attribute index based on a stream of attributes. */ 121/* NOTE: Policy not used ! */ 122int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, 123 int len, struct nla_policy *policy) 124{ 125 struct nlattr *pos; 126 int rem; 127 128 /* First clear table */ 129 memset(tb, 0, (maxtype + 1) * sizeof(struct nlattr *)); 130 131 nla_for_each_attr(pos, head, len, rem) { 132 int type = nla_type(pos); 133 134 if ((type <= maxtype) && (type != 0)) 135 tb[type] = pos; 136 } 137 138 return 0; 139} 140 141 142/* Create attribute index based on nested attribute. */ 143int nla_parse_nested(struct nlattr *tb[], int maxtype, 144 struct nlattr *nla, struct nla_policy *policy) 145{ 146 return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy); 147} 148 149 150/* Add a unspecific attribute to netlink message. */ 151int nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data) 152{ 153 struct nlattr *nla; 154 155 /* Reserve space and init nla header */ 156 nla = nla_reserve(msg, attrtype, datalen); 157 if (nla) { 158 memcpy(nla_data(nla), data, datalen); 159 return 0; 160 } 161 162 return -EINVAL; 163} 164 165/* Add 8 bit integer attribute to netlink message. */ 166int nla_put_u8(struct nl_msg *msg, int attrtype, uint8_t value) 167{ 168 return nla_put(msg, attrtype, sizeof(uint8_t), &value); 169} 170 171/* Add 16 bit integer attribute to netlink message. */ 172int nla_put_u16(struct nl_msg *msg, int attrtype, uint16_t value) 173{ 174 return nla_put(msg, attrtype, sizeof(uint16_t), &value); 175} 176 177/* Add 32 bit integer attribute to netlink message. */ 178int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value) 179{ 180 return nla_put(msg, attrtype, sizeof(uint32_t), &value); 181} 182 183/* Add 64 bit integer attribute to netlink message. */ 184int nla_put_u64(struct nl_msg *msg, int attrtype, uint64_t value) 185{ 186 return nla_put(msg, attrtype, sizeof(uint64_t), &value); 187} 188 189/* Add nested attributes to netlink message. */ 190/* Takes the attributes found in the nested message and appends them 191 * to the message msg nested in a container of the type attrtype. The 192 * nested message may not have a family specific header */ 193int nla_put_nested(struct nl_msg *msg, int attrtype, struct nl_msg *nested) 194{ 195 int rc; 196 197 rc = nla_put(msg, attrtype, nlmsg_attrlen(nlmsg_hdr(nested), 0), 198 nlmsg_attrdata(nlmsg_hdr(nested), 0)); 199 return rc; 200 201} 202 203/* Return type of the attribute. */ 204int nla_type(const struct nlattr *nla) 205{ 206 return (int)nla->nla_type & NLA_TYPE_MASK; 207} 208 209/* Reserves room for an attribute in specified netlink message and fills 210 * in the attribute header (type,length). Return NULL if insufficient space */ 211struct nlattr *nla_reserve(struct nl_msg *msg, int attrtype, int data_len) 212{ 213 214 struct nlattr *nla; 215 const unsigned int NEW_SIZE = NLMSG_ALIGN(msg->nm_nlh->nlmsg_len) + 216 NLA_ALIGN(NLA_HDRLEN + data_len); 217 218 /* Check enough space for attribute */ 219 if (NEW_SIZE > msg->nm_size) 220 return NULL; 221 222 nla = (struct nlattr *)nlmsg_tail(msg->nm_nlh); 223 nla->nla_type = attrtype; 224 nla->nla_len = NLA_HDRLEN + data_len; 225 memset((unsigned char *)nla + nla->nla_len, 0, nla_padlen(data_len)); 226 msg->nm_nlh->nlmsg_len = NEW_SIZE; 227 return nla; 228} 229 230/* Copy attribute payload to another memory area. */ 231int nla_memcpy(void *dest, struct nlattr *src, int count) 232{ 233 if (!src || !dest) 234 return 0; 235 if (count > nla_len(src)) 236 count = nla_len(src); 237 memcpy(dest, nla_data(src), count); 238 return count; 239} 240