/* * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2015 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef NETLINK_H #define NETLINK_H 1 /* Netlink message helpers. * * Netlink is a datagram-based network protocol primarily for communication * between user processes and the kernel, and mainly on Linux. Netlink is * specified in RFC 3549, "Linux Netlink as an IP Services Protocol". * * Netlink is not suitable for use in physical networks of heterogeneous * machines because host byte order is used throughout. * * This header file defines helper functions for working with Netlink messages. * For Netlink protocol definitions, see netlink-protocol.h. For * Linux-specific definitions for Netlink sockets, see netlink-socket.h. */ #include #include #include #include "netlink-protocol.h" #include "openvswitch/types.h" struct ofpbuf; struct nlattr; /* Accessing headers and data. */ struct nlmsghdr *nl_msg_nlmsghdr(const struct ofpbuf *); struct genlmsghdr *nl_msg_genlmsghdr(const struct ofpbuf *); bool nl_msg_nlmsgerr(const struct ofpbuf *, int *error); void nl_msg_reserve(struct ofpbuf *, size_t); /* Appending and prepending headers and raw data. */ void nl_msg_put_nlmsghdr(struct ofpbuf *, size_t expected_payload, uint32_t type, uint32_t flags); void nl_msg_put_genlmsghdr(struct ofpbuf *, size_t expected_payload, int family, uint32_t flags, uint8_t cmd, uint8_t version); void nl_msg_put(struct ofpbuf *, const void *, size_t); void *nl_msg_put_uninit(struct ofpbuf *, size_t); void nl_msg_push(struct ofpbuf *, const void *, size_t); void *nl_msg_push_uninit(struct ofpbuf *, size_t); /* Appending attributes. */ void *nl_msg_put_unspec_uninit(struct ofpbuf *, uint16_t type, size_t); void *nl_msg_put_unspec_zero(struct ofpbuf *, uint16_t type, size_t); void nl_msg_put_unspec(struct ofpbuf *, uint16_t type, const void *, size_t); void nl_msg_put_flag(struct ofpbuf *, uint16_t type); void nl_msg_put_u8(struct ofpbuf *, uint16_t type, uint8_t value); void nl_msg_put_u16(struct ofpbuf *, uint16_t type, uint16_t value); void nl_msg_put_u32(struct ofpbuf *, uint16_t type, uint32_t value); void nl_msg_put_u64(struct ofpbuf *, uint16_t type, uint64_t value); void nl_msg_put_be16(struct ofpbuf *, uint16_t type, ovs_be16 value); void nl_msg_put_be32(struct ofpbuf *, uint16_t type, ovs_be32 value); void nl_msg_put_be64(struct ofpbuf *, uint16_t type, ovs_be64 value); void nl_msg_put_odp_port(struct ofpbuf *, uint16_t type, odp_port_t value); void nl_msg_put_string(struct ofpbuf *, uint16_t type, const char *value); size_t nl_msg_start_nested(struct ofpbuf *, uint16_t type); void nl_msg_end_nested(struct ofpbuf *, size_t offset); void nl_msg_put_nested(struct ofpbuf *, uint16_t type, const void *data, size_t size); /* Prepending attributes. */ void *nl_msg_push_unspec_uninit(struct ofpbuf *, uint16_t type, size_t); void nl_msg_push_unspec(struct ofpbuf *, uint16_t type, const void *, size_t); void nl_msg_push_flag(struct ofpbuf *, uint16_t type); void nl_msg_push_u8(struct ofpbuf *, uint16_t type, uint8_t value); void nl_msg_push_u16(struct ofpbuf *, uint16_t type, uint16_t value); void nl_msg_push_u32(struct ofpbuf *, uint16_t type, uint32_t value); void nl_msg_push_u64(struct ofpbuf *, uint16_t type, uint64_t value); void nl_msg_push_be16(struct ofpbuf *, uint16_t type, ovs_be16 value); void nl_msg_push_be32(struct ofpbuf *, uint16_t type, ovs_be32 value); void nl_msg_push_be64(struct ofpbuf *, uint16_t type, ovs_be64 value); void nl_msg_push_string(struct ofpbuf *, uint16_t type, const char *value); /* Separating buffers into individual messages. */ struct nlmsghdr *nl_msg_next(struct ofpbuf *buffer, struct ofpbuf *msg); /* Sizes of various attribute types, in bytes, including the attribute header * and padding. * * A minimum-size attribute is 4 bytes long: 4 bytes of header, no bytes of * payload, no padding. * * A maximum-size attribute is 65536 bytes long: 4 bytes of header, 65531 bytes * of payload, 1 byte of padding. (Thus, NL_ATTR_SIZE() of a maximum length * attribute payload does not fit in 16 bits.) */ #define NL_ATTR_SIZE(PAYLOAD_SIZE) (NLA_HDRLEN + NLA_ALIGN(PAYLOAD_SIZE)) #define NL_A_U8_SIZE NL_ATTR_SIZE(sizeof(uint8_t)) #define NL_A_U16_SIZE NL_ATTR_SIZE(sizeof(uint16_t)) #define NL_A_U32_SIZE NL_ATTR_SIZE(sizeof(uint32_t)) #define NL_A_U64_SIZE NL_ATTR_SIZE(sizeof(uint64_t)) #define NL_A_BE16_SIZE NL_ATTR_SIZE(sizeof(ovs_be16)) #define NL_A_BE32_SIZE NL_ATTR_SIZE(sizeof(ovs_be32)) #define NL_A_BE64_SIZE NL_ATTR_SIZE(sizeof(ovs_be64)) #define NL_A_FLAG_SIZE NL_ATTR_SIZE(0) bool nl_attr_oversized(size_t payload_size); /* Netlink attribute types. */ enum nl_attr_type { NL_A_NO_ATTR = 0, NL_A_UNSPEC, NL_A_U8, NL_A_U16, NL_A_BE16 = NL_A_U16, NL_A_U32, NL_A_BE32 = NL_A_U32, NL_A_U64, NL_A_BE64 = NL_A_U64, NL_A_STRING, NL_A_FLAG, NL_A_NESTED, N_NL_ATTR_TYPES }; /* Netlink attribute iteration. */ static inline struct nlattr * nl_attr_next(const struct nlattr *nla) { return (void *) ((uint8_t *) nla + NLA_ALIGN(nla->nla_len)); } static inline bool nl_attr_is_valid(const struct nlattr *nla, size_t maxlen) { return (maxlen >= sizeof *nla && nla->nla_len >= sizeof *nla && nla->nla_len <= maxlen); } static inline size_t nl_attr_len_pad(const struct nlattr *nla, size_t maxlen) { size_t len = NLA_ALIGN(nla->nla_len); return len <= maxlen ? len : nla->nla_len; } /* This macro is careful to check for attributes with bad lengths. */ #define NL_ATTR_FOR_EACH(ITER, LEFT, ATTRS, ATTRS_LEN) \ for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ nl_attr_is_valid(ITER, LEFT); \ (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER)) /* This macro does not check for attributes with bad lengths. It should only * be used with messages from trusted sources or with messages that have * already been validated (e.g. with NL_ATTR_FOR_EACH). */ #define NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, ATTRS, ATTRS_LEN) \ for ((ITER) = (ATTRS), (LEFT) = (ATTRS_LEN); \ (LEFT) > 0; \ (LEFT) -= nl_attr_len_pad(ITER, LEFT), (ITER) = nl_attr_next(ITER)) /* These variants are convenient for iterating nested attributes. */ #define NL_NESTED_FOR_EACH(ITER, LEFT, A) \ NL_ATTR_FOR_EACH(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A)) #define NL_NESTED_FOR_EACH_UNSAFE(ITER, LEFT, A) \ NL_ATTR_FOR_EACH_UNSAFE(ITER, LEFT, nl_attr_get(A), nl_attr_get_size(A)) /* Netlink attribute parsing. */ int nl_attr_type(const struct nlattr *); const void *nl_attr_get(const struct nlattr *); size_t nl_attr_get_size(const struct nlattr *); const void *nl_attr_get_unspec(const struct nlattr *, size_t size); bool nl_attr_get_flag(const struct nlattr *); uint8_t nl_attr_get_u8(const struct nlattr *); uint16_t nl_attr_get_u16(const struct nlattr *); uint32_t nl_attr_get_u32(const struct nlattr *); uint64_t nl_attr_get_u64(const struct nlattr *); ovs_be16 nl_attr_get_be16(const struct nlattr *); ovs_be32 nl_attr_get_be32(const struct nlattr *); ovs_be64 nl_attr_get_be64(const struct nlattr *); odp_port_t nl_attr_get_odp_port(const struct nlattr *); const char *nl_attr_get_string(const struct nlattr *); void nl_attr_get_nested(const struct nlattr *, struct ofpbuf *); /* Netlink attribute policy. * * Specifies how to parse a single attribute from a Netlink message payload. */ struct nl_policy { enum nl_attr_type type; size_t min_len, max_len; bool optional; }; #define NL_POLICY_FOR(TYPE) \ .type = NL_A_UNSPEC, .min_len = sizeof(TYPE), .max_len = sizeof(TYPE) bool nl_attr_validate(const struct nlattr *, const struct nl_policy *); bool nl_policy_parse(const struct ofpbuf *, size_t offset, const struct nl_policy[], struct nlattr *[], size_t n_attrs); bool nl_parse_nested(const struct nlattr *, const struct nl_policy[], struct nlattr *[], size_t n_attrs); const struct nlattr *nl_attr_find(const struct ofpbuf *, size_t hdr_len, uint16_t type); const struct nlattr *nl_attr_find_nested(const struct nlattr *, uint16_t type); const struct nlattr *nl_attr_find__(const struct nlattr *attrs, size_t size, uint16_t type); #endif /* netlink.h */