From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04DE3C7619B for ; Sun, 16 Feb 2020 22:47:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBF4A2072C for ; Sun, 16 Feb 2020 22:47:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728175AbgBPWrI (ORCPT ); Sun, 16 Feb 2020 17:47:08 -0500 Received: from mx2.suse.de ([195.135.220.15]:33792 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728135AbgBPWrI (ORCPT ); Sun, 16 Feb 2020 17:47:08 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 375ADAF55; Sun, 16 Feb 2020 22:47:06 +0000 (UTC) Received: by unicorn.suse.cz (Postfix, from userid 1000) id D76D5E03D6; Sun, 16 Feb 2020 23:47:05 +0100 (CET) Message-Id: <243e6cdd79a02065acca55a79407baac7d17b316.1581892124.git.mkubecek@suse.cz> In-Reply-To: References: From: Michal Kubecek Subject: [PATCH ethtool 07/19] netlink: message buffer and composition helpers To: John Linville , netdev@vger.kernel.org Cc: Andrew Lunn , Florian Fainelli Date: Sun, 16 Feb 2020 23:47:05 +0100 (CET) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add data structure for flexible message buffer and helpers for safe message composition. The nl_msg_buff structure is an abstraction for a message buffer used to compose an outgoing netlink message. When the message exceeds currently allocated length, buffer is reallocated. Only if the buffer size reaches MAX_MSG_SIZE (4 MB), an error is issued. Signed-off-by: Michal Kubecek --- Makefile.am | 1 + netlink/msgbuff.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++ netlink/msgbuff.h | 106 +++++++++++++++++++++++++++++ netlink/netlink.h | 1 + 4 files changed, 277 insertions(+) create mode 100644 netlink/msgbuff.c create mode 100644 netlink/msgbuff.h diff --git a/Makefile.am b/Makefile.am index 3748d0df5608..12412b433445 100644 --- a/Makefile.am +++ b/Makefile.am @@ -27,6 +27,7 @@ endif if ETHTOOL_ENABLE_NETLINK ethtool_SOURCES += \ netlink/netlink.c netlink/netlink.h netlink/extapi.h \ + netlink/msgbuff.c netlink/msgbuff.h \ uapi/linux/ethtool_netlink.h \ uapi/linux/netlink.h uapi/linux/genetlink.h ethtool_CFLAGS += @MNL_CFLAGS@ diff --git a/netlink/msgbuff.c b/netlink/msgbuff.c new file mode 100644 index 000000000000..1e73354d194b --- /dev/null +++ b/netlink/msgbuff.c @@ -0,0 +1,169 @@ +/* + * 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 */ + +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; +} + +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; + + 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; +} + +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; +} + +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; +} + +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; +} + +/* initialize a genetlink message and fill netlink and genetlink header */ +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; +} + +/* simplified wrapper to initialize an ethtool netlink message */ +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); +} + +void msgbuff_init(struct nl_msg_buff *msgbuff) +{ + memset(msgbuff, '\0', sizeof(*msgbuff)); +} + +void msgbuff_done(struct nl_msg_buff *msgbuff) +{ + free(msgbuff->buff); + msgbuff->buff = NULL; + msgbuff->size = 0; + msgbuff->left = 0; +} diff --git a/netlink/msgbuff.h b/netlink/msgbuff.h new file mode 100644 index 000000000000..6f3baa9992fd --- /dev/null +++ b/netlink/msgbuff.h @@ -0,0 +1,106 @@ +/* + * msgbuff.h - netlink message buffer + * + * Declarations of netlink message buffer and related functions. + */ + +#ifndef ETHTOOL_NETLINK_MSGBUFF_H__ +#define ETHTOOL_NETLINK_MSGBUFF_H__ + +#include +#include +#include +#include + +struct nl_context; + +struct nl_msg_buff { + char *buff; + unsigned int size; + unsigned int left; + struct nlmsghdr *nlhdr; + struct genlmsghdr *genlhdr; + void *payload; +}; + +void msgbuff_init(struct nl_msg_buff *msgbuff); +void msgbuff_done(struct nl_msg_buff *msgbuff); +int msgbuff_realloc(struct nl_msg_buff *msgbuff, unsigned int new_size); +int msgbuff_append(struct nl_msg_buff *dest, struct nl_msg_buff *src); + +int __msg_init(struct nl_msg_buff *msgbuff, int family, int cmd, + unsigned int flags, int version); +int msg_init(struct nl_context *nlctx, struct nl_msg_buff *msgbuff, int cmd, + unsigned int flags); + +bool ethnla_put(struct nl_msg_buff *msgbuff, uint16_t type, size_t len, + const void *data); +struct nlattr *ethnla_nest_start(struct nl_msg_buff *msgbuff, uint16_t type); +bool ethnla_fill_header(struct nl_msg_buff *msgbuff, uint16_t type, + const char *devname, uint32_t flags); + +static inline unsigned int msgbuff_len(const struct nl_msg_buff *msgbuff) +{ + return msgbuff->nlhdr->nlmsg_len; +} + +static inline void msgbuff_reset(const struct nl_msg_buff *msgbuff, + unsigned int len) +{ + msgbuff->nlhdr->nlmsg_len = len; +} + +/* put data wrappers */ + +static inline void ethnla_nest_end(struct nl_msg_buff *msgbuff, + struct nlattr *nest) +{ + return mnl_attr_nest_end(msgbuff->nlhdr, nest); +} + +static inline void ethnla_nest_cancel(struct nl_msg_buff *msgbuff, + struct nlattr *nest) +{ + return mnl_attr_nest_cancel(msgbuff->nlhdr, nest); +} + +static inline bool ethnla_put_u32(struct nl_msg_buff *msgbuff, uint16_t type, + uint32_t data) +{ + return ethnla_put(msgbuff, type, sizeof(uint32_t), &data); +} + +static inline bool ethnla_put_u8(struct nl_msg_buff *msgbuff, uint16_t type, + uint8_t data) +{ + return ethnla_put(msgbuff, type, sizeof(uint8_t), &data); +} + +static inline bool ethnla_put_flag(struct nl_msg_buff *msgbuff, uint16_t type, + bool val) +{ + if (val) + return ethnla_put(msgbuff, type, 0, &val); + else + return false; +} + +static inline bool ethnla_put_bitfield32(struct nl_msg_buff *msgbuff, + uint16_t type, uint32_t value, + uint32_t selector) +{ + struct nla_bitfield32 val = { + .value = value, + .selector = selector, + }; + + return ethnla_put(msgbuff, type, sizeof(val), &val); +} + +static inline bool ethnla_put_strz(struct nl_msg_buff *msgbuff, uint16_t type, + const char *data) +{ + return ethnla_put(msgbuff, type, strlen(data) + 1, data); +} + +#endif /* ETHTOOL_NETLINK_MSGBUFF_H__ */ diff --git a/netlink/netlink.h b/netlink/netlink.h index 610beccbefda..48c4ebb3d7aa 100644 --- a/netlink/netlink.h +++ b/netlink/netlink.h @@ -21,6 +21,7 @@ struct nl_context { bool is_dump; int exit_code; bool suppress_nlerr; + uint16_t ethnl_fam; }; #endif /* ETHTOOL_NETLINK_INT_H__ */ -- 2.25.0