On 09/26, Daniel Borkmann wrote: > Add a basic netlink helper library for the BPF selftests. This has been > taken and cut down/cleaned up from iproute2. More can be added at some > later point in time when needed, but for now this covers basics such as > device creation which we need for BPF selftests / BPF CI. Should the netlink code be based on ynl (https://lore.kernel.org/all/20230825122756.7603-1-donald.hunter@xxxxxxxxx/)? Or it doesn't have full rtnl support yet? > > Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > --- > tools/testing/selftests/bpf/Makefile | 19 +- > tools/testing/selftests/bpf/netlink_helpers.c | 358 ++++++++++++++++++ > tools/testing/selftests/bpf/netlink_helpers.h | 46 +++ > 3 files changed, 418 insertions(+), 5 deletions(-) > create mode 100644 tools/testing/selftests/bpf/netlink_helpers.c > create mode 100644 tools/testing/selftests/bpf/netlink_helpers.h > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > index 47365161b6fc..b8186ceb31dc 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -579,11 +579,20 @@ endef > # Define test_progs test runner. > TRUNNER_TESTS_DIR := prog_tests > TRUNNER_BPF_PROGS_DIR := progs > -TRUNNER_EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c \ > - network_helpers.c testing_helpers.c \ > - btf_helpers.c flow_dissector_load.h \ > - cap_helpers.c test_loader.c xsk.c disasm.c \ > - json_writer.c unpriv_helpers.c \ > +TRUNNER_EXTRA_SOURCES := test_progs.c \ > + cgroup_helpers.c \ > + trace_helpers.c \ > + network_helpers.c \ > + testing_helpers.c \ > + btf_helpers.c \ > + cap_helpers.c \ > + unpriv_helpers.c \ > + netlink_helpers.c \ > + test_loader.c \ > + xsk.c \ > + disasm.c \ > + json_writer.c \ > + flow_dissector_load.h \ > ip_check_defrag_frags.h > TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/bpf_testmod.ko \ > $(OUTPUT)/liburandom_read.so \ > diff --git a/tools/testing/selftests/bpf/netlink_helpers.c b/tools/testing/selftests/bpf/netlink_helpers.c > new file mode 100644 > index 000000000000..caf36eb1d032 > --- /dev/null > +++ b/tools/testing/selftests/bpf/netlink_helpers.c > @@ -0,0 +1,358 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* Taken & modified from iproute2's libnetlink.c > + * Authors: Alexey Kuznetsov, <kuznet@xxxxxxxxxxxxx> > + */ > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > +#include <errno.h> > +#include <time.h> > +#include <sys/socket.h> > + > +#include "netlink_helpers.h" > + > +static int rcvbuf = 1024 * 1024; > + > +void rtnl_close(struct rtnl_handle *rth) > +{ > + if (rth->fd >= 0) { > + close(rth->fd); > + rth->fd = -1; > + } > +} > + > +int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions, > + int protocol) > +{ > + socklen_t addr_len; > + int sndbuf = 32768; > + int one = 1; > + > + memset(rth, 0, sizeof(*rth)); > + rth->proto = protocol; > + rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol); > + if (rth->fd < 0) { > + perror("Cannot open netlink socket"); > + return -1; > + } > + if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF, > + &sndbuf, sizeof(sndbuf)) < 0) { > + perror("SO_SNDBUF"); > + goto err; > + } > + if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF, > + &rcvbuf, sizeof(rcvbuf)) < 0) { > + perror("SO_RCVBUF"); > + goto err; > + } > + > + /* 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; > + > + if (bind(rth->fd, (struct sockaddr *)&rth->local, > + sizeof(rth->local)) < 0) { > + perror("Cannot bind netlink socket"); > + goto err; > + } > + addr_len = sizeof(rth->local); > + if (getsockname(rth->fd, (struct sockaddr *)&rth->local, > + &addr_len) < 0) { > + perror("Cannot getsockname"); > + goto err; > + } > + if (addr_len != sizeof(rth->local)) { > + fprintf(stderr, "Wrong address length %d\n", addr_len); > + goto err; > + } > + if (rth->local.nl_family != AF_NETLINK) { > + fprintf(stderr, "Wrong address family %d\n", > + rth->local.nl_family); > + goto err; > + } > + rth->seq = time(NULL); > + return 0; > +err: > + rtnl_close(rth); > + return -1; > +} > + > +int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions) > +{ > + return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE); > +} > + > +static int __rtnl_recvmsg(int fd, struct msghdr *msg, int flags) > +{ > + int len; > + > + do { > + len = recvmsg(fd, msg, flags); > + } while (len < 0 && (errno == EINTR || errno == EAGAIN)); > + if (len < 0) { > + fprintf(stderr, "netlink receive error %s (%d)\n", > + strerror(errno), errno); > + return -errno; > + } > + if (len == 0) { > + fprintf(stderr, "EOF on netlink\n"); > + return -ENODATA; > + } > + return len; > +} > + > +static int rtnl_recvmsg(int fd, struct msghdr *msg, char **answer) > +{ > + struct iovec *iov = msg->msg_iov; > + char *buf; > + int len; > + > + iov->iov_base = NULL; > + iov->iov_len = 0; > + > + len = __rtnl_recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC); > + if (len < 0) > + return len; > + if (len < 32768) > + len = 32768; > + buf = malloc(len); > + if (!buf) { > + fprintf(stderr, "malloc error: not enough buffer\n"); > + return -ENOMEM; > + } > + iov->iov_base = buf; > + iov->iov_len = len; > + len = __rtnl_recvmsg(fd, msg, 0); > + if (len < 0) { > + free(buf); > + return len; > + } > + if (answer) > + *answer = buf; > + else > + free(buf); > + return len; > +} > + > +static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err, > + nl_ext_ack_fn_t errfn) > +{ > + fprintf(stderr, "RTNETLINK answers: %s\n", > + strerror(-err->error)); > +} > + > +static int __rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iov, > + size_t iovlen, struct nlmsghdr **answer, > + bool show_rtnl_err, nl_ext_ack_fn_t errfn) > +{ > + struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK }; > + struct iovec riov; > + struct msghdr msg = { > + .msg_name = &nladdr, > + .msg_namelen = sizeof(nladdr), > + .msg_iov = iov, > + .msg_iovlen = iovlen, > + }; > + unsigned int seq = 0; > + struct nlmsghdr *h; > + int i, status; > + char *buf; > + > + for (i = 0; i < iovlen; i++) { > + h = iov[i].iov_base; > + h->nlmsg_seq = seq = ++rtnl->seq; > + if (answer == NULL) > + h->nlmsg_flags |= NLM_F_ACK; > + } > + status = sendmsg(rtnl->fd, &msg, 0); > + if (status < 0) { > + perror("Cannot talk to rtnetlink"); > + return -1; > + } > + /* change msg to use the response iov */ > + msg.msg_iov = &riov; > + msg.msg_iovlen = 1; > + i = 0; > + while (1) { > +next: > + status = rtnl_recvmsg(rtnl->fd, &msg, &buf); > + ++i; > + if (status < 0) > + return status; > + if (msg.msg_namelen != sizeof(nladdr)) { > + fprintf(stderr, > + "Sender address length == %d!\n", > + msg.msg_namelen); > + exit(1); > + } > + for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) { > + int len = h->nlmsg_len; > + int l = len - sizeof(*h); > + > + if (l < 0 || len > status) { > + if (msg.msg_flags & MSG_TRUNC) { > + fprintf(stderr, "Truncated message!\n"); > + free(buf); > + return -1; > + } > + fprintf(stderr, > + "Malformed message: len=%d!\n", > + len); > + exit(1); > + } > + if (nladdr.nl_pid != 0 || > + h->nlmsg_pid != rtnl->local.nl_pid || > + h->nlmsg_seq > seq || h->nlmsg_seq < seq - iovlen) { > + /* Don't forget to skip that message. */ > + status -= NLMSG_ALIGN(len); > + h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len)); > + continue; > + } > + if (h->nlmsg_type == NLMSG_ERROR) { > + struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h); > + int error = err->error; > + > + if (l < sizeof(struct nlmsgerr)) { > + fprintf(stderr, "ERROR truncated\n"); > + free(buf); > + return -1; > + } > + if (error) { > + errno = -error; > + if (rtnl->proto != NETLINK_SOCK_DIAG && > + show_rtnl_err) > + rtnl_talk_error(h, err, errfn); > + } > + if (i < iovlen) { > + free(buf); > + goto next; > + } > + if (error) { > + free(buf); > + return -i; > + } > + if (answer) > + *answer = (struct nlmsghdr *)buf; > + else > + free(buf); > + return 0; > + } > + if (answer) { > + *answer = (struct nlmsghdr *)buf; > + return 0; > + } > + fprintf(stderr, "Unexpected reply!\n"); > + status -= NLMSG_ALIGN(len); > + h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len)); > + } > + free(buf); > + if (msg.msg_flags & MSG_TRUNC) { > + fprintf(stderr, "Message truncated!\n"); > + continue; > + } > + if (status) { > + fprintf(stderr, "Remnant of size %d!\n", status); > + exit(1); > + } > + } > +} > + > +static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, > + struct nlmsghdr **answer, bool show_rtnl_err, > + nl_ext_ack_fn_t errfn) > +{ > + struct iovec iov = { > + .iov_base = n, > + .iov_len = n->nlmsg_len, > + }; > + > + return __rtnl_talk_iov(rtnl, &iov, 1, answer, show_rtnl_err, errfn); > +} > + > +int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, > + struct nlmsghdr **answer) > +{ > + return __rtnl_talk(rtnl, n, answer, true, NULL); > +} > + > +int addattr(struct nlmsghdr *n, int maxlen, int type) > +{ > + return addattr_l(n, maxlen, type, NULL, 0); > +} > + > +int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data) > +{ > + return addattr_l(n, maxlen, type, &data, sizeof(__u8)); > +} > + > +int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data) > +{ > + return addattr_l(n, maxlen, type, &data, sizeof(__u16)); > +} > + > +int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data) > +{ > + return addattr_l(n, maxlen, type, &data, sizeof(__u32)); > +} > + > +int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data) > +{ > + return addattr_l(n, maxlen, type, &data, sizeof(__u64)); > +} > + > +int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str) > +{ > + return addattr_l(n, maxlen, type, str, strlen(str)+1); > +} > + > +int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data, > + int alen) > +{ > + int len = RTA_LENGTH(alen); > + struct rtattr *rta; > + > + if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) { > + fprintf(stderr, "%s: Message exceeded bound of %d\n", > + __func__, maxlen); > + return -1; > + } > + rta = NLMSG_TAIL(n); > + rta->rta_type = type; > + rta->rta_len = len; > + if (alen) > + memcpy(RTA_DATA(rta), data, alen); > + n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len); > + return 0; > +} > + > +int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len) > +{ > + if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) { > + fprintf(stderr, "%s: Message exceeded bound of %d\n", > + __func__, maxlen); > + return -1; > + } > + > + memcpy(NLMSG_TAIL(n), data, len); > + memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len); > + n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len); > + return 0; > +} > + > +struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type) > +{ > + struct rtattr *nest = NLMSG_TAIL(n); > + > + addattr_l(n, maxlen, type, NULL, 0); > + return nest; > +} > + > +int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest) > +{ > + nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest; > + return n->nlmsg_len; > +} > diff --git a/tools/testing/selftests/bpf/netlink_helpers.h b/tools/testing/selftests/bpf/netlink_helpers.h > new file mode 100644 > index 000000000000..68116818a47e > --- /dev/null > +++ b/tools/testing/selftests/bpf/netlink_helpers.h > @@ -0,0 +1,46 @@ > +/* SPDX-License-Identifier: GPL-2.0-or-later */ > +#ifndef NETLINK_HELPERS_H > +#define NETLINK_HELPERS_H > + > +#include <string.h> > +#include <linux/netlink.h> > +#include <linux/rtnetlink.h> > + > +struct rtnl_handle { > + int fd; > + struct sockaddr_nl local; > + struct sockaddr_nl peer; > + __u32 seq; > + __u32 dump; > + int proto; > + FILE *dump_fp; > +#define RTNL_HANDLE_F_LISTEN_ALL_NSID 0x01 > +#define RTNL_HANDLE_F_SUPPRESS_NLERR 0x02 > +#define RTNL_HANDLE_F_STRICT_CHK 0x04 > + int flags; > +}; > + > +#define NLMSG_TAIL(nmsg) \ > + ((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len))) > + > +typedef int (*nl_ext_ack_fn_t)(const char *errmsg, uint32_t off, > + const struct nlmsghdr *inner_nlh); > + > +int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions) > + __attribute__((warn_unused_result)); > +void rtnl_close(struct rtnl_handle *rth); > +int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, > + struct nlmsghdr **answer) > + __attribute__((warn_unused_result)); > + > +int addattr(struct nlmsghdr *n, int maxlen, int type); > +int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data); > +int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data); > +int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data); > +int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data); > +int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *data); > +int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data, int alen); > +int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len); > +struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type); > +int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest); > +#endif /* NETLINK_HELPERS_H */ > -- > 2.34.1 >
