1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2021 Ng Peng Nam Sean 5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _NETLINK_NETLINK_MESSAGE_WRITER_H_ 30 #define _NETLINK_NETLINK_MESSAGE_WRITER_H_ 31 32 #ifdef _KERNEL 33 /* 34 * It is not meant to be included directly 35 */ 36 37 struct mbuf; 38 struct nl_writer; 39 typedef bool nl_writer_cb(struct nl_writer *nw, void *buf, int buflen, int cnt); 40 41 struct nl_writer { 42 int alloc_len; /* allocated buffer length */ 43 int offset; /* offset from the start of the buffer */ 44 struct nlmsghdr *hdr; /* Pointer to the currently-filled msg */ 45 char *data; /* pointer to the contiguous storage */ 46 void *_storage; /* Underlying storage pointer */ 47 nl_writer_cb *cb; /* Callback to flush data */ 48 union { 49 void *arg_ptr; /* Callback argument as pointer */ 50 uint64_t arg_uint; /* Callback argument as int */ 51 }; 52 int num_messages; /* Number of messages in the buffer */ 53 int malloc_flag; /* M_WAITOK or M_NOWAIT */ 54 uint8_t writer_type; /* NS_WRITER_TYPE_* */ 55 uint8_t writer_target; /* NS_WRITER_TARGET_* */ 56 bool ignore_limit; /* If true, ignores RCVBUF limit */ 57 bool enomem; /* True if ENOMEM occured */ 58 }; 59 #define NS_WRITER_TARGET_SOCKET 0 60 #define NS_WRITER_TARGET_GROUP 1 61 #define NS_WRITER_TARGET_CHAIN 2 62 63 #define NS_WRITER_TYPE_MBUF 0 64 #define NS_WRITER_TYPE_BUF 1 65 #define NS_WRITER_TYPE_LBUF 2 66 #define NS_WRITER_TYPE_MBUFC 3 67 68 69 #define NLMSG_SMALL 128 70 #define NLMSG_LARGE 2048 71 72 /* Message and attribute writing */ 73 74 struct nlpcb; 75 bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp); 76 bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id); 77 bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm); 78 bool nlmsg_flush(struct nl_writer *nw); 79 void nlmsg_ignore_limit(struct nl_writer *nw); 80 81 bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size); 82 bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type, 83 uint16_t flags, uint32_t len); 84 bool nlmsg_end(struct nl_writer *nw); 85 void nlmsg_abort(struct nl_writer *nw); 86 87 bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr); 88 89 static inline bool 90 nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len) 91 { 92 return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type, 93 hdr->nlmsg_flags, payload_len)); 94 } 95 96 #define nlmsg_data(_hdr) ((void *)((_hdr) + 1)) 97 98 /* 99 * KPI similar to mtodo(): 100 * current (uncompleted) header is guaranteed to be contiguous, 101 * but can be reallocated, thus pointers may need to be readjusted. 102 */ 103 static inline int 104 nlattr_save_offset(const struct nl_writer *nw) 105 { 106 return (nw->offset - ((char *)nw->hdr - nw->data)); 107 } 108 109 static inline void * 110 _nlattr_restore_offset(const struct nl_writer *nw, int off) 111 { 112 return ((void *)((char *)nw->hdr + off)); 113 } 114 #define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off)) 115 116 static inline void 117 nlattr_set_len(const struct nl_writer *nw, int off) 118 { 119 struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr); 120 nla->nla_len = nlattr_save_offset(nw) - off; 121 } 122 123 static inline void * 124 nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz) 125 { 126 if (__predict_false(nw->offset + NETLINK_ALIGN(sz) > nw->alloc_len)) { 127 if (!nlmsg_refill_buffer(nw, NETLINK_ALIGN(sz))) 128 return (NULL); 129 } 130 131 void *data_ptr = &nw->data[nw->offset]; 132 nw->offset += NLMSG_ALIGN(sz); 133 134 return (data_ptr); 135 } 136 #define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, NLA_ALIGN(sizeof(_t)))) 137 #define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz)) 138 139 static inline int 140 nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type) 141 { 142 int off = nlattr_save_offset(nw); 143 struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr); 144 if (__predict_false(nla == NULL)) 145 return (0); 146 nla->nla_type = nla_type; 147 return (off); 148 } 149 150 static inline void * 151 _nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz) 152 { 153 sz += sizeof(struct nlattr); 154 155 struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr); 156 if (__predict_false(nla == NULL)) 157 return (NULL); 158 nla->nla_type = nla_type; 159 nla->nla_len = sz; 160 161 return ((void *)(nla + 1)); 162 } 163 #define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t)))) 164 165 static inline bool 166 nlattr_add(struct nl_writer *nw, int attr_type, int attr_len, const void *data) 167 { 168 int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr)); 169 170 if (__predict_false(nw->offset + required_len > nw->alloc_len)) { 171 if (!nlmsg_refill_buffer(nw, required_len)) 172 return (false); 173 } 174 175 struct nlattr *nla = (struct nlattr *)(&nw->data[nw->offset]); 176 177 nla->nla_len = attr_len + sizeof(struct nlattr); 178 nla->nla_type = attr_type; 179 if (attr_len > 0) { 180 if ((attr_len % 4) != 0) { 181 /* clear padding bytes */ 182 bzero((char *)nla + required_len - 4, 4); 183 } 184 memcpy((nla + 1), data, attr_len); 185 } 186 nw->offset += required_len; 187 return (true); 188 } 189 190 static inline bool 191 nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value) 192 { 193 return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value)); 194 } 195 196 static inline bool 197 nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value) 198 { 199 return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value)); 200 } 201 202 static inline bool 203 nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value) 204 { 205 return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value)); 206 } 207 208 static inline bool 209 nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value) 210 { 211 return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value)); 212 } 213 214 static inline bool 215 nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value) 216 { 217 return (nlattr_add(nw, attrtype, sizeof(int8_t), &value)); 218 } 219 220 static inline bool 221 nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value) 222 { 223 return (nlattr_add(nw, attrtype, sizeof(int16_t), &value)); 224 } 225 226 static inline bool 227 nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value) 228 { 229 return (nlattr_add(nw, attrtype, sizeof(int32_t), &value)); 230 } 231 232 static inline bool 233 nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value) 234 { 235 return (nlattr_add(nw, attrtype, sizeof(int64_t), &value)); 236 } 237 238 static inline bool 239 nlattr_add_flag(struct nl_writer *nw, int attrtype) 240 { 241 return (nlattr_add(nw, attrtype, 0, NULL)); 242 } 243 244 static inline bool 245 nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str) 246 { 247 return (nlattr_add(nw, attrtype, strlen(str) + 1, str)); 248 } 249 250 251 #endif 252 #endif 253