From: Stephen Hemminger Date: Fri, 4 Aug 2017 16:52:15 +0000 (-0700) Subject: iproute: Add support for extended ack to rtnl_talk X-Git-Tag: v4.13.0~86 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b6432e68ac2f1f6b4ea50aa0d6d47e72c445c71c;p=thirdparty%2Fiproute2.git iproute: Add support for extended ack to rtnl_talk Add support for extended ack error reporting via libmnl. Add a new function rtnl_talk_extack that takes a callback as an input arg. If a netlink response contains extack attributes, the callback is is invoked with the the err string, offset in the message and a pointer to the message returned by the kernel. If iproute2 is built without libmnl, it will still work but extended error reports from kernel will not be available. Signed-off-by: Stephen Hemminger --- diff --git a/include/libnetlink.h b/include/libnetlink.h index 643c3bc56..69257f0e6 100644 --- a/include/libnetlink.h +++ b/include/libnetlink.h @@ -76,6 +76,9 @@ typedef int (*rtnl_listen_filter_t)(const struct sockaddr_nl *, struct rtnl_ctrl_data *, struct nlmsghdr *n, void *); +typedef int (*nl_ext_ack_fn_t)(const char *errmsg, uint32_t off, + const struct nlmsghdr *inner_nlh); + struct rtnl_dump_filter_arg { rtnl_filter_t filter; void *arg1; @@ -92,6 +95,9 @@ int rtnl_dump_filter_nc(struct rtnl_handle *rth, int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr *answer, size_t len) __attribute__((warn_unused_result)); +int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n, + struct nlmsghdr *answer, size_t len, nl_ext_ack_fn_t errfn) + __attribute__((warn_unused_result)); int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr *answer, size_t len) __attribute__((warn_unused_result)); diff --git a/lib/Makefile b/lib/Makefile index 1d24ca24b..f81888cca 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -4,6 +4,13 @@ ifeq ($(IP_CONFIG_SETNS),y) CFLAGS += -DHAVE_SETNS endif +ifeq ($(HAVE_MNL),y) + CFLAGS += $(shell $(PKG_CONFIG) libmnl --cflags) + LDLIBS += $(shell $(PKG_CONFIG) libmnl --libs) +else +@warn "libmnl required for error support" +endif + CFLAGS += -fPIC UTILOBJ = utils.o rt_names.o ll_types.o ll_proto.o ll_addr.o \ diff --git a/lib/libnetlink.c b/lib/libnetlink.c index d4b831f67..41353b7db 100644 --- a/lib/libnetlink.c +++ b/lib/libnetlink.c @@ -36,6 +36,79 @@ int rcvbuf = 1024 * 1024; +#ifdef HAVE_LIBMNL +#include + +static const enum mnl_attr_data_type extack_policy[NLMSGERR_ATTR_MAX + 1] = { + [NLMSGERR_ATTR_MSG] = MNL_TYPE_NUL_STRING, + [NLMSGERR_ATTR_OFFS] = MNL_TYPE_U32, +}; + +static int err_attr_cb(const struct nlattr *attr, void *data) +{ + const struct nlattr **tb = data; + uint16_t type; + + if (mnl_attr_type_valid(attr, NLMSGERR_ATTR_MAX) < 0) + return MNL_CB_ERROR; + + type = mnl_attr_get_type(attr); + if (mnl_attr_validate(attr, extack_policy[type]) < 0) + return MNL_CB_ERROR; + + + tb[type] = attr; + return MNL_CB_OK; +} + + +/* dump netlink extended ack error message */ +static int nl_dump_ext_err(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn) +{ + struct nlattr *tb[NLMSGERR_ATTR_MAX + 1]; + const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh); + const struct nlmsghdr *err_nlh = NULL; + unsigned int hlen = sizeof(*err); + const char *errmsg = NULL; + uint32_t off = 0; + + if (!errfn) + return 0; + + /* no TLVs, nothing to do here */ + if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS)) + return 0; + + /* if NLM_F_CAPPED is set then the inner err msg was capped */ + if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) + hlen += mnl_nlmsg_get_payload_len(&err->msg); + + mnl_attr_parse(nlh, hlen, err_attr_cb, tb); + + if (tb[NLMSGERR_ATTR_MSG]) + errmsg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]); + + if (tb[NLMSGERR_ATTR_OFFS]) { + off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]); + + if (off > nlh->nlmsg_len) { + fprintf(stderr, + "Invalid offset for NLMSGERR_ATTR_OFFS\n"); + off = 0; + } else if (!(nlh->nlmsg_flags & NLM_F_CAPPED)) + err_nlh = &err->msg; + } + + return errfn(errmsg, off, err_nlh); +} +#else +/* No extended error ack without libmnl */ +static int nl_dump_ext_err(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn) +{ + return 0; +} +#endif + void rtnl_close(struct rtnl_handle *rth) { if (rth->fd >= 0) { @@ -49,6 +122,7 @@ int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions, { socklen_t addr_len; int sndbuf = 32768; + int one = 1; memset(rth, 0, sizeof(*rth)); @@ -71,6 +145,10 @@ int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions, return -1; } + /* Older kernels may no support extended ACK reporting */ + setsockopt(rth->fd, SOL_NETLINK, NETLINK_EXT_ACK, + &one, sizeof(one)); + memset(&rth->local, 0, sizeof(rth->local)); rth->local.nl_family = AF_NETLINK; rth->local.nl_groups = subscriptions; @@ -423,9 +501,19 @@ int rtnl_dump_filter_nc(struct rtnl_handle *rth, return rtnl_dump_filter_l(rth, a); } +static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err, + nl_ext_ack_fn_t errfn) +{ + if (nl_dump_ext_err(h, errfn)) + return; + + fprintf(stderr, "RTNETLINK answers: %s\n", + strerror(-err->error)); +} + static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr *answer, size_t maxlen, - bool show_rtnl_err) + bool show_rtnl_err, nl_ext_ack_fn_t errfn) { int status; unsigned int seq; @@ -512,10 +600,10 @@ static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, return 0; } - if (rtnl->proto != NETLINK_SOCK_DIAG && show_rtnl_err) - fprintf(stderr, - "RTNETLINK answers: %s\n", - strerror(-err->error)); + if (rtnl->proto != NETLINK_SOCK_DIAG && + show_rtnl_err) + rtnl_talk_error(h, err, errfn); + errno = -err->error; return -1; } @@ -547,13 +635,20 @@ static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr *answer, size_t maxlen) { - return __rtnl_talk(rtnl, n, answer, maxlen, true); + return __rtnl_talk(rtnl, n, answer, maxlen, true, NULL); +} + +int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n, + struct nlmsghdr *answer, size_t maxlen, + nl_ext_ack_fn_t errfn) +{ + return __rtnl_talk(rtnl, n, answer, maxlen, true, errfn); } int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n, struct nlmsghdr *answer, size_t maxlen) { - return __rtnl_talk(rtnl, n, answer, maxlen, false); + return __rtnl_talk(rtnl, n, answer, maxlen, false, NULL); } int rtnl_listen_all_nsid(struct rtnl_handle *rth)