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 bool suppress_ack; /* If true, don't send NLMSG_ERR */ 59 }; 60 #define NS_WRITER_TARGET_SOCKET 0 61 #define NS_WRITER_TARGET_GROUP 1 62 #define NS_WRITER_TARGET_CHAIN 2 63 64 #define NS_WRITER_TYPE_MBUF 0 65 #define NS_WRITER_TYPE_BUF 1 66 #define NS_WRITER_TYPE_LBUF 2 67 #define NS_WRITER_TYPE_MBUFC 3 68 69 70 #define NLMSG_SMALL 128 71 #define NLMSG_LARGE 2048 72 73 /* Message and attribute writing */ 74 75 struct nlpcb; 76 bool nlmsg_get_unicast_writer(struct nl_writer *nw, int expected_size, struct nlpcb *nlp); 77 bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id); 78 bool nlmsg_get_chain_writer(struct nl_writer *nw, int expected_size, struct mbuf **pm); 79 bool nlmsg_flush(struct nl_writer *nw); 80 void nlmsg_ignore_limit(struct nl_writer *nw); 81 82 bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size); 83 bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type, 84 uint16_t flags, uint32_t len); 85 bool nlmsg_end(struct nl_writer *nw); 86 void nlmsg_abort(struct nl_writer *nw); 87 88 bool nlmsg_end_dump(struct nl_writer *nw, int error, struct nlmsghdr *hdr); 89 90 static inline bool 91 nlmsg_reply(struct nl_writer *nw, const struct nlmsghdr *hdr, int payload_len) 92 { 93 return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type, 94 hdr->nlmsg_flags, payload_len)); 95 } 96 97 #define nlmsg_data(_hdr) ((void *)((_hdr) + 1)) 98 99 /* 100 * KPI similar to mtodo(): 101 * current (uncompleted) header is guaranteed to be contiguous, 102 * but can be reallocated, thus pointers may need to be readjusted. 103 */ 104 static inline int 105 nlattr_save_offset(const struct nl_writer *nw) 106 { 107 return (nw->offset - ((char *)nw->hdr - nw->data)); 108 } 109 110 static inline void * 111 _nlattr_restore_offset(const struct nl_writer *nw, int off) 112 { 113 return ((void *)((char *)nw->hdr + off)); 114 } 115 #define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off)) 116 117 static inline void 118 nlattr_set_len(const struct nl_writer *nw, int off) 119 { 120 struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr); 121 nla->nla_len = nlattr_save_offset(nw) - off; 122 } 123 124 static inline void * 125 nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz) 126 { 127 if (__predict_false(nw->offset + NETLINK_ALIGN(sz) > nw->alloc_len)) { 128 if (!nlmsg_refill_buffer(nw, NETLINK_ALIGN(sz))) 129 return (NULL); 130 } 131 132 void *data_ptr = &nw->data[nw->offset]; 133 nw->offset += NLMSG_ALIGN(sz); 134 135 return (data_ptr); 136 } 137 #define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, NLA_ALIGN(sizeof(_t)))) 138 #define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz)) 139 140 static inline int 141 nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type) 142 { 143 int off = nlattr_save_offset(nw); 144 struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr); 145 if (__predict_false(nla == NULL)) 146 return (0); 147 nla->nla_type = nla_type; 148 return (off); 149 } 150 151 static inline void * 152 _nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz) 153 { 154 sz += sizeof(struct nlattr); 155 156 struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr); 157 if (__predict_false(nla == NULL)) 158 return (NULL); 159 nla->nla_type = nla_type; 160 nla->nla_len = sz; 161 162 return ((void *)(nla + 1)); 163 } 164 #define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t)))) 165 166 static inline bool 167 nlattr_add(struct nl_writer *nw, int attr_type, int attr_len, const void *data) 168 { 169 int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr)); 170 171 if (__predict_false(nw->offset + required_len > nw->alloc_len)) { 172 if (!nlmsg_refill_buffer(nw, required_len)) 173 return (false); 174 } 175 176 struct nlattr *nla = (struct nlattr *)(&nw->data[nw->offset]); 177 178 nla->nla_len = attr_len + sizeof(struct nlattr); 179 nla->nla_type = attr_type; 180 if (attr_len > 0) { 181 if ((attr_len % 4) != 0) { 182 /* clear padding bytes */ 183 bzero((char *)nla + required_len - 4, 4); 184 } 185 memcpy((nla + 1), data, attr_len); 186 } 187 nw->offset += required_len; 188 return (true); 189 } 190 191 static inline bool 192 nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value) 193 { 194 return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value)); 195 } 196 197 static inline bool 198 nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value) 199 { 200 return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value)); 201 } 202 203 static inline bool 204 nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value) 205 { 206 return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value)); 207 } 208 209 static inline bool 210 nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value) 211 { 212 return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value)); 213 } 214 215 static inline bool 216 nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value) 217 { 218 return (nlattr_add(nw, attrtype, sizeof(int8_t), &value)); 219 } 220 221 static inline bool 222 nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value) 223 { 224 return (nlattr_add(nw, attrtype, sizeof(int16_t), &value)); 225 } 226 227 static inline bool 228 nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value) 229 { 230 return (nlattr_add(nw, attrtype, sizeof(int32_t), &value)); 231 } 232 233 static inline bool 234 nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value) 235 { 236 return (nlattr_add(nw, attrtype, sizeof(int64_t), &value)); 237 } 238 239 static inline bool 240 nlattr_add_flag(struct nl_writer *nw, int attrtype) 241 { 242 return (nlattr_add(nw, attrtype, 0, NULL)); 243 } 244 245 static inline bool 246 nlattr_add_string(struct nl_writer *nw, int attrtype, const char *str) 247 { 248 return (nlattr_add(nw, attrtype, strlen(str) + 1, str)); 249 } 250 251 252 #endif 253 #endif 254