diff options
Diffstat (limited to 'netlink/netlink.c')
| -rw-r--r-- | netlink/netlink.c | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/netlink/netlink.c b/netlink/netlink.c new file mode 100644 index 0000000..ef0d825 --- /dev/null +++ b/netlink/netlink.c @@ -0,0 +1,527 @@ +/* + * netlink.c - basic infrastructure for netlink code + * + * Heart of the netlink interface implementation. + */ + +#include <errno.h> + +#include "../internal.h" +#include "netlink.h" +#include "extapi.h" +#include "msgbuff.h" +#include "nlsock.h" +#include "strset.h" + +/* Used as reply callback for requests where no reply is expected (e.g. most + * "set" type commands) + */ +int nomsg_reply_cb(const struct nlmsghdr *nlhdr, void *data __maybe_unused) +{ + const struct genlmsghdr *ghdr = (const struct genlmsghdr *)(nlhdr + 1); + + fprintf(stderr, "received unexpected message: len=%u type=%u cmd=%u\n", + nlhdr->nlmsg_len, nlhdr->nlmsg_type, ghdr->cmd); + return MNL_CB_OK; +} + +/* standard attribute parser callback; it fills provided array with pointers + * to attributes like kernel nla_parse(). We must expect to run on top of + * a newer kernel which may send attributes that we do not know (yet). Rather + * than treating them as an error, just ignore them. + */ +int attr_cb(const struct nlattr *attr, void *data) +{ + const struct attr_tb_info *tb_info = data; + uint16_t type = mnl_attr_get_type(attr); + + if (type <= tb_info->max_type) + tb_info->tb[type] = attr; + + return MNL_CB_OK; +} + +/* misc helpers */ + +const char *get_dev_name(const struct nlattr *nest) +{ + const struct nlattr *tb[ETHTOOL_A_HEADER_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(tb); + int ret; + + if (!nest) + return NULL; + ret = mnl_attr_parse_nested(nest, attr_cb, &tb_info); + if (ret < 0 || !tb[ETHTOOL_A_HEADER_DEV_NAME]) + return "(none)"; + return mnl_attr_get_str(tb[ETHTOOL_A_HEADER_DEV_NAME]); +} + +int get_dev_info(const struct nlattr *nest, int *ifindex, char *ifname) +{ + const struct nlattr *tb[ETHTOOL_A_HEADER_MAX + 1] = {}; + const struct nlattr *index_attr; + const struct nlattr *name_attr; + DECLARE_ATTR_TB_INFO(tb); + int ret; + + if (ifindex) + *ifindex = 0; + if (ifname) + memset(ifname, '\0', ALTIFNAMSIZ); + + if (!nest) + return -EFAULT; + ret = mnl_attr_parse_nested(nest, attr_cb, &tb_info); + index_attr = tb[ETHTOOL_A_HEADER_DEV_INDEX]; + name_attr = tb[ETHTOOL_A_HEADER_DEV_NAME]; + if (ret < 0 || (ifindex && !index_attr) || (ifname && !name_attr)) + return -EFAULT; + + if (ifindex) + *ifindex = mnl_attr_get_u32(index_attr); + if (ifname) { + strncpy(ifname, mnl_attr_get_str(name_attr), ALTIFNAMSIZ); + if (ifname[ALTIFNAMSIZ - 1]) { + ifname[ALTIFNAMSIZ - 1] = '\0'; + fprintf(stderr, "kernel device name too long: '%s'\n", + mnl_attr_get_str(name_attr)); + return -EFAULT; + } + } + return 0; +} + +/** + * netlink_cmd_check() - check support for netlink command + * @ctx: ethtool command context + * @cmd: netlink command id + * @devname: device name from user + * @allow_wildcard: wildcard dumps supported + * + * Check if command @cmd is known to be unsupported based on ops information + * from genetlink family id request. Set nlctx->ioctl_fallback if ethtool + * should fall back to ioctl, i.e. when we do not know in advance that + * netlink request is supported. Set nlctx->wildcard_unsupported if "*" was + * used as device name but the request does not support wildcards (on either + * side). + * + * Return: true if we know the netlink request is not supported and should + * fail (and possibly fall back) without actually sending it to kernel. + */ +bool netlink_cmd_check(struct cmd_context *ctx, unsigned int cmd, + bool allow_wildcard) +{ + bool is_dump = !strcmp(ctx->devname, WILDCARD_DEVNAME); + uint32_t cap = is_dump ? GENL_CMD_CAP_DUMP : GENL_CMD_CAP_DO; + struct nl_context *nlctx = ctx->nlctx; + + if (is_dump && !allow_wildcard) { + nlctx->wildcard_unsupported = true; + return true; + } + if (!nlctx->ops_info) { + nlctx->ioctl_fallback = true; + return false; + } + if (cmd > ETHTOOL_MSG_USER_MAX || !nlctx->ops_info[cmd].op_flags) { + nlctx->ioctl_fallback = true; + return true; + } + + if (is_dump && !(nlctx->ops_info[cmd].op_flags & GENL_CMD_CAP_DUMP)) + nlctx->wildcard_unsupported = true; + + return !(nlctx->ops_info[cmd].op_flags & cap); +} + +struct ethtool_op_policy_query_ctx { + struct nl_context *nlctx; + unsigned int op; + unsigned int op_hdr_attr; + + bool op_policy_found; + bool hdr_policy_found; + unsigned int op_policy_idx; + unsigned int hdr_policy_idx; + uint64_t flag_mask; +}; + +static int family_policy_find_op(struct ethtool_op_policy_query_ctx *policy_ctx, + const struct nlattr *op_policy) +{ + const struct nlattr *attr; + unsigned int type; + int ret; + + type = policy_ctx->nlctx->is_dump ? + CTRL_ATTR_POLICY_DUMP : CTRL_ATTR_POLICY_DO; + + mnl_attr_for_each_nested(attr, op_policy) { + const struct nlattr *tb[CTRL_ATTR_POLICY_DUMP_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(tb); + + if (mnl_attr_get_type(attr) != policy_ctx->op) + continue; + + ret = mnl_attr_parse_nested(attr, attr_cb, &tb_info); + if (ret < 0) + return ret; + + if (!tb[type]) + continue; + + policy_ctx->op_policy_found = true; + policy_ctx->op_policy_idx = mnl_attr_get_u32(tb[type]); + break; + } + + return 0; +} + +static int family_policy_cb(const struct nlmsghdr *nlhdr, void *data) +{ + const struct nlattr *tba[NL_POLICY_TYPE_ATTR_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(tba); + const struct nlattr *tb[CTRL_ATTR_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(tb); + struct ethtool_op_policy_query_ctx *policy_ctx = data; + const struct nlattr *policy_attr, *attr_attr, *attr; + unsigned int attr_idx, policy_idx; + int ret; + + ret = mnl_attr_parse(nlhdr, GENL_HDRLEN, attr_cb, &tb_info); + if (ret < 0) + return MNL_CB_ERROR; + + if (!policy_ctx->op_policy_found) { + if (!tb[CTRL_ATTR_OP_POLICY]) { + fprintf(stderr, "Error: op policy map not present\n"); + return MNL_CB_ERROR; + } + ret = family_policy_find_op(policy_ctx, tb[CTRL_ATTR_OP_POLICY]); + return ret < 0 ? MNL_CB_ERROR : MNL_CB_OK; + } + + if (!tb[CTRL_ATTR_POLICY]) + return MNL_CB_OK; + + policy_attr = mnl_attr_get_payload(tb[CTRL_ATTR_POLICY]); + policy_idx = mnl_attr_get_type(policy_attr); + attr_attr = mnl_attr_get_payload(policy_attr); + attr_idx = mnl_attr_get_type(attr_attr); + + ret = mnl_attr_parse_nested(attr_attr, attr_cb, &tba_info); + if (ret < 0) + return MNL_CB_ERROR; + + if (policy_idx == policy_ctx->op_policy_idx && + attr_idx == policy_ctx->op_hdr_attr) { + attr = tba[NL_POLICY_TYPE_ATTR_POLICY_IDX]; + if (!attr) { + fprintf(stderr, "Error: no policy index in what was expected to be ethtool header attribute\n"); + return MNL_CB_ERROR; + } + policy_ctx->hdr_policy_found = true; + policy_ctx->hdr_policy_idx = mnl_attr_get_u32(attr); + } + + if (policy_ctx->hdr_policy_found && + policy_ctx->hdr_policy_idx == policy_idx && + attr_idx == ETHTOOL_A_HEADER_FLAGS) { + attr = tba[NL_POLICY_TYPE_ATTR_MASK]; + if (!attr) { + fprintf(stderr, "Error: validation mask not reported for ethtool header flags\n"); + return MNL_CB_ERROR; + } + + policy_ctx->flag_mask = mnl_attr_get_u64(attr); + } + + return MNL_CB_OK; +} + +static int read_flags_policy(struct nl_context *nlctx, struct nl_socket *nlsk, + unsigned int nlcmd, unsigned int hdrattr) +{ + struct ethtool_op_policy_query_ctx policy_ctx; + struct nl_msg_buff *msgbuff = &nlsk->msgbuff; + int ret; + + if (nlctx->ops_info[nlcmd].hdr_policy_loaded) + return 0; + + memset(&policy_ctx, 0, sizeof(policy_ctx)); + policy_ctx.nlctx = nlctx; + policy_ctx.op = nlcmd; + policy_ctx.op_hdr_attr = hdrattr; + + ret = __msg_init(msgbuff, GENL_ID_CTRL, CTRL_CMD_GETPOLICY, + NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP, 1); + if (ret < 0) + return ret; + ret = -EMSGSIZE; + if (ethnla_put_u16(msgbuff, CTRL_ATTR_FAMILY_ID, nlctx->ethnl_fam)) + return ret; + if (ethnla_put_u32(msgbuff, CTRL_ATTR_OP, nlcmd)) + return ret; + + nlsock_sendmsg(nlsk, NULL); + nlsock_process_reply(nlsk, family_policy_cb, &policy_ctx); + + nlctx->ops_info[nlcmd].hdr_policy_loaded = 1; + nlctx->ops_info[nlcmd].hdr_flags = policy_ctx.flag_mask; + return 0; +} + +u32 get_stats_flag(struct nl_context *nlctx, unsigned int nlcmd, + unsigned int hdrattr) +{ + if (!nlctx->ctx->show_stats) + return 0; + if (nlcmd > ETHTOOL_MSG_USER_MAX || + !(nlctx->ops_info[nlcmd].op_flags & GENL_CMD_CAP_HASPOL)) + return 0; + + if (read_flags_policy(nlctx, nlctx->ethnl_socket, nlcmd, hdrattr) < 0) + return 0; + + return nlctx->ops_info[nlcmd].hdr_flags & ETHTOOL_FLAG_STATS; +} + +/* initialization */ + +static int genl_read_ops(struct nl_context *nlctx, + const struct nlattr *ops_attr) +{ + struct nl_op_info *ops_info; + struct nlattr *op_attr; + int ret; + + ops_info = calloc(__ETHTOOL_MSG_USER_CNT, sizeof(ops_info[0])); + if (!ops_info) + return -ENOMEM; + + mnl_attr_for_each_nested(op_attr, ops_attr) { + const struct nlattr *tb[CTRL_ATTR_OP_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(tb); + uint32_t op_id; + + ret = mnl_attr_parse_nested(op_attr, attr_cb, &tb_info); + if (ret < 0) + goto err; + + if (!tb[CTRL_ATTR_OP_ID] || !tb[CTRL_ATTR_OP_FLAGS]) + continue; + op_id = mnl_attr_get_u32(tb[CTRL_ATTR_OP_ID]); + if (op_id >= __ETHTOOL_MSG_USER_CNT) + continue; + + ops_info[op_id].op_flags = + mnl_attr_get_u32(tb[CTRL_ATTR_OP_FLAGS]); + } + + nlctx->ops_info = ops_info; + return 0; +err: + free(ops_info); + return ret; +} + +static void find_mc_group(struct nl_context *nlctx, struct nlattr *nest) +{ + const struct nlattr *grp_tb[CTRL_ATTR_MCAST_GRP_MAX + 1] = {}; + DECLARE_ATTR_TB_INFO(grp_tb); + struct nlattr *grp_attr; + int ret; + + mnl_attr_for_each_nested(grp_attr, nest) { + ret = mnl_attr_parse_nested(grp_attr, attr_cb, &grp_tb_info); + if (ret < 0) + return; + if (!grp_tb[CTRL_ATTR_MCAST_GRP_NAME] || + !grp_tb[CTRL_ATTR_MCAST_GRP_ID]) + continue; + if (strcmp(mnl_attr_get_str(grp_tb[CTRL_ATTR_MCAST_GRP_NAME]), + ETHTOOL_MCGRP_MONITOR_NAME)) + continue; + nlctx->ethnl_mongrp = + mnl_attr_get_u32(grp_tb[CTRL_ATTR_MCAST_GRP_ID]); + return; + } +} + +static int __maybe_unused family_info_cb(const struct nlmsghdr *nlhdr, + void *data) +{ + struct nl_context *nlctx = data; + struct nlattr *attr; + int ret; + + mnl_attr_for_each(attr, nlhdr, GENL_HDRLEN) { + switch (mnl_attr_get_type(attr)) { + case CTRL_ATTR_FAMILY_ID: + nlctx->ethnl_fam = mnl_attr_get_u16(attr); + break; + case CTRL_ATTR_OPS: + ret = genl_read_ops(nlctx, attr); + if (ret < 0) + return MNL_CB_ERROR; + break; + case CTRL_ATTR_MCAST_GROUPS: + find_mc_group(nlctx, attr); + break; + } + } + + return MNL_CB_OK; +} + +#ifdef TEST_ETHTOOL +static int get_genl_family(struct nl_context *nlctx __maybe_unused, + struct nl_socket *nlsk __maybe_unused) +{ + return 0; +} +#else +static int get_genl_family(struct nl_context *nlctx, struct nl_socket *nlsk) +{ + struct nl_msg_buff *msgbuff = &nlsk->msgbuff; + int ret; + + nlctx->suppress_nlerr = 2; + ret = __msg_init(msgbuff, GENL_ID_CTRL, CTRL_CMD_GETFAMILY, + NLM_F_REQUEST | NLM_F_ACK, 1); + if (ret < 0) + goto out; + ret = -EMSGSIZE; + if (ethnla_put_strz(msgbuff, CTRL_ATTR_FAMILY_NAME, ETHTOOL_GENL_NAME)) + goto out; + + nlsock_sendmsg(nlsk, NULL); + nlsock_process_reply(nlsk, family_info_cb, nlctx); + ret = nlctx->ethnl_fam ? 0 : -EADDRNOTAVAIL; + +out: + nlctx->suppress_nlerr = 0; + return ret; +} +#endif + +int netlink_init(struct cmd_context *ctx) +{ + struct nl_context *nlctx; + int ret; + + nlctx = calloc(1, sizeof(*nlctx)); + if (!nlctx) + return -ENOMEM; + nlctx->ctx = ctx; + ret = nlsock_init(nlctx, &nlctx->ethnl_socket, NETLINK_GENERIC); + if (ret < 0) + goto out_free; + ret = get_genl_family(nlctx, nlctx->ethnl_socket); + if (ret < 0) + goto out_nlsk; + + ctx->nlctx = nlctx; + return 0; + +out_nlsk: + nlsock_done(nlctx->ethnl_socket); +out_free: + free(nlctx->ops_info); + free(nlctx); + return ret; +} + +static void netlink_done(struct cmd_context *ctx) +{ + struct nl_context *nlctx = ctx->nlctx; + + if (!nlctx) + return; + + nlsock_done(nlctx->ethnl_socket); + nlsock_done(nlctx->ethnl2_socket); + nlsock_done(nlctx->rtnl_socket); + free(nlctx->ops_info); + free(nlctx); + ctx->nlctx = NULL; + cleanup_all_strings(); +} + +/** + * netlink_run_handler() - run netlink handler for subcommand + * @ctx: command context + * @nlchk: netlink capability check + * @nlfunc: subcommand netlink handler to call + * @no_fallback: there is no ioctl fallback handler + * + * This function returns only if ioctl() handler should be run as fallback. + * Otherwise it exits with appropriate return code. + */ +void netlink_run_handler(struct cmd_context *ctx, nl_chk_t nlchk, + nl_func_t nlfunc, bool no_fallback) +{ + bool wildcard = ctx->devname && !strcmp(ctx->devname, WILDCARD_DEVNAME); + bool wildcard_unsupported, ioctl_fallback; + struct nl_context *nlctx; + const char *reason; + int ret; + + if (nlchk && !nlchk(ctx)) { + reason = "ioctl-only request"; + goto no_support; + } + if (ctx->devname && strlen(ctx->devname) >= ALTIFNAMSIZ) { + fprintf(stderr, "device name '%s' longer than %u characters\n", + ctx->devname, ALTIFNAMSIZ - 1); + exit(1); + } + + if (!nlfunc) { + reason = "ethtool netlink support for subcommand missing"; + goto no_support; + } + if (netlink_init(ctx)) { + reason = "netlink interface initialization failed"; + goto no_support; + } + nlctx = ctx->nlctx; + + ret = nlfunc(ctx); + wildcard_unsupported = nlctx->wildcard_unsupported; + ioctl_fallback = nlctx->ioctl_fallback; + netlink_done(ctx); + + if (no_fallback || ret != -EOPNOTSUPP || !ioctl_fallback) { + if (wildcard_unsupported) + fprintf(stderr, "%s\n", + "subcommand does not support wildcard dump"); + exit(ret >= 0 ? ret : 1); + } + if (wildcard_unsupported) + reason = "subcommand does not support wildcard dump"; + else + reason = "kernel netlink support for subcommand missing"; + +no_support: + if (no_fallback) { + fprintf(stderr, "%s, subcommand not supported by ioctl\n", + reason); + exit(1); + } + if (wildcard) { + fprintf(stderr, "%s, wildcard dump not supported\n", reason); + exit(1); + } + if (ctx->devname && strlen(ctx->devname) >= IFNAMSIZ) { + fprintf(stderr, + "%s, device name longer than %u not supported\n", + reason, IFNAMSIZ - 1); + exit(1); + } + + /* fallback to ioctl() */ +} |