From: Ben Pfaff Date: Mon, 26 Sep 2011 19:57:41 +0000 (-0700) Subject: netlink: New functions for putting attributes at the beginning of a buffer. X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=46d34fefc1bd8e0f5329d4c22d59a286e3bbb260;p=openvswitch netlink: New functions for putting attributes at the beginning of a buffer. These are really just copies of the corresponding "put" functions. An upcoming commit will introduce a user of nl_msg_push_u32(). I thought I might as well create all of these while I was at it. --- diff --git a/lib/netlink.c b/lib/netlink.c index b4de3ed7..7529534b 100644 --- a/lib/netlink.c +++ b/lib/netlink.c @@ -201,6 +201,29 @@ nl_msg_put_uninit(struct ofpbuf *msg, size_t size) return p; } +/* Prepends the 'size' bytes of data in 'p', plus Netlink padding if needed, to + * the head end of 'msg'. Data in 'msg' is reallocated and copied if + * necessary. */ +void +nl_msg_push(struct ofpbuf *msg, const void *data, size_t size) +{ + memcpy(nl_msg_push_uninit(msg, size), data, size); +} + +/* Prepends 'size' bytes of data, plus Netlink padding if needed, to the head + * end of 'msg', reallocating and copying its data if necessary. Returns a + * pointer to the first byte of the new data, which is left uninitialized. */ +void * +nl_msg_push_uninit(struct ofpbuf *msg, size_t size) +{ + size_t pad = NLMSG_ALIGN(size) - size; + char *p = ofpbuf_push_uninit(msg, size + pad); + if (pad) { + memset(p + size, 0, pad); + } + return p; +} + /* Appends a Netlink attribute of the given 'type' and room for 'size' bytes of * data as its payload, plus Netlink padding if needed, to the tail end of * 'msg', reallocating and copying its data if necessary. Returns a pointer to @@ -300,6 +323,105 @@ nl_msg_put_string(struct ofpbuf *msg, uint16_t type, const char *value) nl_msg_put_unspec(msg, type, value, strlen(value) + 1); } +/* Prepends a Netlink attribute of the given 'type' and room for 'size' bytes + * of data as its payload, plus Netlink padding if needed, to the head end of + * 'msg', reallocating and copying its data if necessary. Returns a pointer to + * the first byte of data in the attribute, which is left uninitialized. */ +void * +nl_msg_push_unspec_uninit(struct ofpbuf *msg, uint16_t type, size_t size) +{ + size_t total_size = NLA_HDRLEN + size; + struct nlattr* nla = nl_msg_push_uninit(msg, total_size); + assert(NLA_ALIGN(total_size) <= UINT16_MAX); + nla->nla_len = total_size; + nla->nla_type = type; + return nla + 1; +} + +/* Prepends a Netlink attribute of the given 'type' and the 'size' bytes of + * 'data' as its payload, to the head end of 'msg', reallocating and copying + * its data if necessary. Returns a pointer to the first byte of data in the + * attribute, which is left uninitialized. */ +void +nl_msg_push_unspec(struct ofpbuf *msg, uint16_t type, + const void *data, size_t size) +{ + memcpy(nl_msg_push_unspec_uninit(msg, type, size), data, size); +} + +/* Prepends a Netlink attribute of the given 'type' and no payload to 'msg'. + * (Some Netlink protocols use the presence or absence of an attribute as a + * Boolean flag.) */ +void +nl_msg_push_flag(struct ofpbuf *msg, uint16_t type) +{ + nl_msg_push_unspec(msg, type, NULL, 0); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 8-bit 'value' + * to 'msg'. */ +void +nl_msg_push_u8(struct ofpbuf *msg, uint16_t type, uint8_t value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 16-bit host + * byte order 'value' to 'msg'. */ +void +nl_msg_push_u16(struct ofpbuf *msg, uint16_t type, uint16_t value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 32-bit host + * byte order 'value' to 'msg'. */ +void +nl_msg_push_u32(struct ofpbuf *msg, uint16_t type, uint32_t value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 64-bit host + * byte order 'value' to 'msg'. */ +void +nl_msg_push_u64(struct ofpbuf *msg, uint16_t type, uint64_t value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 16-bit + * network byte order 'value' to 'msg'. */ +void +nl_msg_push_be16(struct ofpbuf *msg, uint16_t type, ovs_be16 value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 32-bit + * network byte order 'value' to 'msg'. */ +void +nl_msg_push_be32(struct ofpbuf *msg, uint16_t type, ovs_be32 value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given 64-bit + * network byte order 'value' to 'msg'. */ +void +nl_msg_push_be64(struct ofpbuf *msg, uint16_t type, ovs_be64 value) +{ + nl_msg_push_unspec(msg, type, &value, sizeof value); +} + +/* Prepends a Netlink attribute of the given 'type' and the given + * null-terminated string 'value' to 'msg'. */ +void +nl_msg_push_string(struct ofpbuf *msg, uint16_t type, const char *value) +{ + nl_msg_push_unspec(msg, type, value, strlen(value) + 1); +} + /* Adds the header for nested Netlink attributes to 'msg', with the specified * 'type', and returns the header's offset within 'msg'. The caller should add * the content for the nested Netlink attribute to 'msg' (e.g. using the other diff --git a/lib/netlink.h b/lib/netlink.h index 2d345716..188a9639 100644 --- a/lib/netlink.h +++ b/lib/netlink.h @@ -46,7 +46,7 @@ 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 headers and raw data. */ +/* 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, @@ -54,6 +54,8 @@ void nl_msg_put_genlmsghdr(struct ofpbuf *, size_t expected_payload, 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); @@ -73,6 +75,19 @@ 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);