From 2a5fcae954f992cf558eb91c83aa4c5a880a6bdc Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:50:40 +0200 Subject: Adding upstream version 1:6.1. Signed-off-by: Daniel Baumann --- netlink/msgbuff.c | 256 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 256 insertions(+) create mode 100644 netlink/msgbuff.c (limited to 'netlink/msgbuff.c') diff --git a/netlink/msgbuff.c b/netlink/msgbuff.c new file mode 100644 index 0000000..216f5b9 --- /dev/null +++ b/netlink/msgbuff.c @@ -0,0 +1,256 @@ +/* + * msgbuff.c - netlink message buffer + * + * Data structures and code for flexible message buffer abstraction. + */ + +#include +#include +#include +#include + +#include "../internal.h" +#include "netlink.h" +#include "msgbuff.h" + +#define MAX_MSG_SIZE (4 << 20) /* 4 MB */ + +/** + * msgbuff_realloc() - reallocate buffer if needed + * @msgbuff: message buffer + * @new_size: requested minimum size (add MNL_SOCKET_BUFFER_SIZE if zero) + * + * Make sure allocated buffer has size at least @new_size. If @new_size is + * shorter than current size, do nothing. If @new_size is 0, grow buffer by + * MNL_SOCKET_BUFFER_SIZE. Fail if new size would exceed MAX_MSG_SIZE. + * + * Return: 0 on success or negative error code + */ +int msgbuff_realloc(struct nl_msg_buff *msgbuff, unsigned int new_size) +{ + unsigned int nlhdr_off, genlhdr_off, payload_off; + unsigned int old_size = msgbuff->size; + char *nbuff; + + nlhdr_off = (char *)msgbuff->nlhdr - msgbuff->buff; + genlhdr_off = (char *)msgbuff->genlhdr - msgbuff->buff; + payload_off = (char *)msgbuff->payload - msgbuff->buff; + + if (!new_size) + new_size = old_size + MNL_SOCKET_BUFFER_SIZE; + if (new_size <= old_size) + return 0; + if (new_size > MAX_MSG_SIZE) + return -EMSGSIZE; + nbuff = realloc(msgbuff->buff, new_size); + if (!nbuff) { + msgbuff->buff = NULL; + msgbuff->size = 0; + msgbuff->left = 0; + return -ENOMEM; + } + if (nbuff != msgbuff->buff) { + if (new_size > old_size) + memset(nbuff + old_size, '\0', new_size - old_size); + msgbuff->nlhdr = (struct nlmsghdr *)(nbuff + nlhdr_off); + msgbuff->genlhdr = (struct genlmsghdr *)(nbuff + genlhdr_off); + msgbuff->payload = nbuff + payload_off; + msgbuff->buff = nbuff; + } + msgbuff->size = new_size; + msgbuff->left += (new_size - old_size); + + return 0; +} + +/** + * msgbuff_append() - add contents of another message buffer + * @dest: target message buffer + * @src: source message buffer + * + * Append contents of @src at the end of @dest. Fail if target buffer cannot + * be reallocated to sufficient size. + * + * Return: 0 on success or negative error code. + */ +int msgbuff_append(struct nl_msg_buff *dest, struct nl_msg_buff *src) +{ + unsigned int src_len = mnl_nlmsg_get_payload_len(src->nlhdr); + unsigned int dest_len = MNL_ALIGN(msgbuff_len(dest)); + int ret; + + src_len -= GENL_HDRLEN; + ret = msgbuff_realloc(dest, dest_len + src_len); + if (ret < 0) + return ret; + memcpy(mnl_nlmsg_get_payload_tail(dest->nlhdr), src->payload, src_len); + msgbuff_reset(dest, dest_len + src_len); + + return 0; +} + +/** + * ethnla_put - write a netlink attribute to message buffer + * @msgbuff: message buffer + * @type: attribute type + * @len: attribute payload length + * @data: attribute payload + * + * Appends a netlink attribute with header to message buffer, reallocates + * if needed. This is mostly used via specific ethnla_put_* wrappers for + * basic data types. + * + * Return: false on success, true on error (reallocation failed) + */ +bool ethnla_put(struct nl_msg_buff *msgbuff, uint16_t type, size_t len, + const void *data) +{ + struct nlmsghdr *nlhdr = msgbuff->nlhdr; + + while (!mnl_attr_put_check(nlhdr, msgbuff->left, type, len, data)) { + int ret = msgbuff_realloc(msgbuff, 0); + + if (ret < 0) + return true; + } + + return false; +} + +/** + * ethnla_nest_start - start a nested attribute + * @msgbuff: message buffer + * @type: nested attribute type (NLA_F_NESTED is added automatically) + * + * Return: pointer to the nest attribute or null of error + */ +struct nlattr *ethnla_nest_start(struct nl_msg_buff *msgbuff, uint16_t type) +{ + struct nlmsghdr *nlhdr = msgbuff->nlhdr; + struct nlattr *attr; + + do { + attr = mnl_attr_nest_start_check(nlhdr, msgbuff->left, type); + if (attr) + return attr; + } while (msgbuff_realloc(msgbuff, 0) == 0); + + return NULL; +} + +/** + * ethnla_fill_header() - write standard ethtool request header to message + * @msgbuff: message buffer + * @type: attribute type for header nest + * @devname: device name (NULL to omit) + * @flags: request flags (omitted if 0) + * + * Return: pointer to the nest attribute or null of error + */ +bool ethnla_fill_header(struct nl_msg_buff *msgbuff, uint16_t type, + const char *devname, uint32_t flags) +{ + struct nlattr *nest; + + nest = ethnla_nest_start(msgbuff, type); + if (!nest) + return true; + + if ((devname && + ethnla_put_strz(msgbuff, ETHTOOL_A_HEADER_DEV_NAME, devname)) || + (flags && + ethnla_put_u32(msgbuff, ETHTOOL_A_HEADER_FLAGS, flags))) + goto err; + + ethnla_nest_end(msgbuff, nest); + return false; + +err: + ethnla_nest_cancel(msgbuff, nest); + return true; +} + +/** + * __msg_init() - init a genetlink message, fill netlink and genetlink header + * @msgbuff: message buffer + * @family: genetlink family + * @cmd: genetlink command (genlmsghdr::cmd) + * @flags: netlink flags (nlmsghdr::nlmsg_flags) + * @version: genetlink family version (genlmsghdr::version) + * + * Initialize a new genetlink message, fill netlink and genetlink header and + * set pointers in struct nl_msg_buff. + * + * Return: 0 on success or negative error code. + */ +int __msg_init(struct nl_msg_buff *msgbuff, int family, int cmd, + unsigned int flags, int version) +{ + struct nlmsghdr *nlhdr; + struct genlmsghdr *genlhdr; + int ret; + + ret = msgbuff_realloc(msgbuff, MNL_SOCKET_BUFFER_SIZE); + if (ret < 0) + return ret; + memset(msgbuff->buff, '\0', NLMSG_HDRLEN + GENL_HDRLEN); + + nlhdr = mnl_nlmsg_put_header(msgbuff->buff); + nlhdr->nlmsg_type = family; + nlhdr->nlmsg_flags = flags; + msgbuff->nlhdr = nlhdr; + + genlhdr = mnl_nlmsg_put_extra_header(nlhdr, sizeof(*genlhdr)); + genlhdr->cmd = cmd; + genlhdr->version = version; + msgbuff->genlhdr = genlhdr; + + msgbuff->payload = mnl_nlmsg_get_payload_offset(nlhdr, GENL_HDRLEN); + + return 0; +} + +/** + * msg_init() - init an ethtool netlink message + * @msgbuff: message buffer + * @cmd: genetlink command (genlmsghdr::cmd) + * @flags: netlink flags (nlmsghdr::nlmsg_flags) + * + * Initialize a new ethtool netlink message, fill netlink and genetlink header + * and set pointers in struct nl_msg_buff. + * + * Return: 0 on success or negative error code. + */ +int msg_init(struct nl_context *nlctx, struct nl_msg_buff *msgbuff, int cmd, + unsigned int flags) +{ + return __msg_init(msgbuff, nlctx->ethnl_fam, cmd, flags, + ETHTOOL_GENL_VERSION); +} + +/** + * msgbuff_init() - initialize a message buffer + * @msgbuff: message buffer + * + * Initialize a message buffer structure before first use. Buffer length is + * set to zero and the buffer is not allocated until the first call to + * msgbuff_reallocate(). + */ +void msgbuff_init(struct nl_msg_buff *msgbuff) +{ + memset(msgbuff, '\0', sizeof(*msgbuff)); +} + +/** + * msg_done() - destroy a message buffer + * @msgbuff: message buffer + * + * Free the buffer and reset size and remaining size. + */ +void msgbuff_done(struct nl_msg_buff *msgbuff) +{ + free(msgbuff->buff); + msgbuff->buff = NULL; + msgbuff->size = 0; + msgbuff->left = 0; +} -- cgit v1.2.3