diff options
Diffstat (limited to 'src/libsystemd/sd-netlink/netlink-util.c')
-rw-r--r-- | src/libsystemd/sd-netlink/netlink-util.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c new file mode 100644 index 0000000..cfcf257 --- /dev/null +++ b/src/libsystemd/sd-netlink/netlink-util.c @@ -0,0 +1,760 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "sd-netlink.h" + +#include "fd-util.h" +#include "io-util.h" +#include "memory-util.h" +#include "netlink-internal.h" +#include "netlink-util.h" +#include "parse-util.h" +#include "process-util.h" +#include "strv.h" + +int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) { + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL; + _cleanup_strv_free_ char **alternative_names = NULL; + bool altname_deleted = false; + int r; + + assert(rtnl); + assert(ifindex > 0); + assert(name); + + if (!ifname_valid(name)) + return -EINVAL; + + r = rtnl_get_link_alternative_names(rtnl, ifindex, &alternative_names); + if (r < 0) + log_debug_errno(r, "Failed to get alternative names on network interface %i, ignoring: %m", + ifindex); + + if (strv_contains(alternative_names, name)) { + r = rtnl_delete_link_alternative_names(rtnl, ifindex, STRV_MAKE(name)); + if (r < 0) + return log_debug_errno(r, "Failed to remove '%s' from alternative names on network interface %i: %m", + name, ifindex); + + altname_deleted = true; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_SETLINK, ifindex); + if (r < 0) + goto fail; + + r = sd_netlink_message_append_string(message, IFLA_IFNAME, name); + if (r < 0) + goto fail; + + r = sd_netlink_call(*rtnl, message, 0, NULL); + if (r < 0) + goto fail; + + return 0; + +fail: + if (altname_deleted) { + int q = rtnl_set_link_alternative_names(rtnl, ifindex, STRV_MAKE(name)); + if (q < 0) + log_debug_errno(q, "Failed to restore '%s' as an alternative name on network interface %i, ignoring: %m", + name, ifindex); + } + + return r; +} + +int rtnl_set_link_properties( + sd_netlink **rtnl, + int ifindex, + const char *alias, + const struct hw_addr_data *hw_addr, + uint32_t txqueues, + uint32_t rxqueues, + uint32_t txqueuelen, + uint32_t mtu, + uint32_t gso_max_size, + size_t gso_max_segments) { + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL; + int r; + + assert(rtnl); + assert(ifindex > 0); + + if (!alias && + (!hw_addr || hw_addr->length == 0) && + txqueues == 0 && + rxqueues == 0 && + txqueuelen == UINT32_MAX && + mtu == 0 && + gso_max_size == 0 && + gso_max_segments == 0) + return 0; + + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_SETLINK, ifindex); + if (r < 0) + return r; + + if (alias) { + r = sd_netlink_message_append_string(message, IFLA_IFALIAS, alias); + if (r < 0) + return r; + } + + if (hw_addr && hw_addr->length > 0) { + r = netlink_message_append_hw_addr(message, IFLA_ADDRESS, hw_addr); + if (r < 0) + return r; + } + + if (txqueues > 0) { + r = sd_netlink_message_append_u32(message, IFLA_NUM_TX_QUEUES, txqueues); + if (r < 0) + return r; + } + + if (rxqueues > 0) { + r = sd_netlink_message_append_u32(message, IFLA_NUM_RX_QUEUES, rxqueues); + if (r < 0) + return r; + } + + if (txqueuelen < UINT32_MAX) { + r = sd_netlink_message_append_u32(message, IFLA_TXQLEN, txqueuelen); + if (r < 0) + return r; + } + + if (mtu != 0) { + r = sd_netlink_message_append_u32(message, IFLA_MTU, mtu); + if (r < 0) + return r; + } + + if (gso_max_size > 0) { + r = sd_netlink_message_append_u32(message, IFLA_GSO_MAX_SIZE, gso_max_size); + if (r < 0) + return r; + } + + if (gso_max_segments > 0) { + r = sd_netlink_message_append_u32(message, IFLA_GSO_MAX_SEGS, gso_max_segments); + if (r < 0) + return r; + } + + r = sd_netlink_call(*rtnl, message, 0, NULL); + if (r < 0) + return r; + + return 0; +} + +int rtnl_get_link_alternative_names(sd_netlink **rtnl, int ifindex, char ***ret) { + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL; + _cleanup_strv_free_ char **names = NULL; + int r; + + assert(rtnl); + assert(ifindex > 0); + assert(ret); + + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex); + if (r < 0) + return r; + + r = sd_netlink_call(*rtnl, message, 0, &reply); + if (r < 0) + return r; + + r = sd_netlink_message_read_strv(reply, IFLA_PROP_LIST, IFLA_ALT_IFNAME, &names); + if (r < 0 && r != -ENODATA) + return r; + + *ret = TAKE_PTR(names); + + return 0; +} + +static int rtnl_update_link_alternative_names( + sd_netlink **rtnl, + uint16_t nlmsg_type, + int ifindex, + char* const *alternative_names) { + + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL; + int r; + + assert(rtnl); + assert(ifindex > 0); + assert(IN_SET(nlmsg_type, RTM_NEWLINKPROP, RTM_DELLINKPROP)); + + if (strv_isempty(alternative_names)) + return 0; + + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, nlmsg_type, ifindex); + if (r < 0) + return r; + + r = sd_netlink_message_open_container(message, IFLA_PROP_LIST); + if (r < 0) + return r; + + r = sd_netlink_message_append_strv(message, IFLA_ALT_IFNAME, (const char**) alternative_names); + if (r < 0) + return r; + + r = sd_netlink_message_close_container(message); + if (r < 0) + return r; + + r = sd_netlink_call(*rtnl, message, 0, NULL); + if (r < 0) + return r; + + return 0; +} + +int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char* const *alternative_names) { + return rtnl_update_link_alternative_names(rtnl, RTM_NEWLINKPROP, ifindex, alternative_names); +} + +int rtnl_delete_link_alternative_names(sd_netlink **rtnl, int ifindex, char* const *alternative_names) { + return rtnl_update_link_alternative_names(rtnl, RTM_DELLINKPROP, ifindex, alternative_names); +} + +int rtnl_set_link_alternative_names_by_ifname( + sd_netlink **rtnl, + const char *ifname, + char* const *alternative_names) { + + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL; + int r; + + assert(rtnl); + assert(ifname); + + if (strv_isempty(alternative_names)) + return 0; + + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_NEWLINKPROP, 0); + if (r < 0) + return r; + + r = sd_netlink_message_append_string(message, IFLA_IFNAME, ifname); + if (r < 0) + return r; + + r = sd_netlink_message_open_container(message, IFLA_PROP_LIST); + if (r < 0) + return r; + + r = sd_netlink_message_append_strv(message, IFLA_ALT_IFNAME, (const char**) alternative_names); + if (r < 0) + return r; + + r = sd_netlink_message_close_container(message); + if (r < 0) + return r; + + r = sd_netlink_call(*rtnl, message, 0, NULL); + if (r < 0) + return r; + + return 0; +} + +int rtnl_resolve_link_alternative_name(sd_netlink **rtnl, const char *name, char **ret) { + _cleanup_(sd_netlink_unrefp) sd_netlink *our_rtnl = NULL; + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL; + int r, ifindex; + + assert(name); + + /* This returns ifindex and the main interface name. */ + + if (!ifname_valid_full(name, IFNAME_VALID_ALTERNATIVE)) + return -EINVAL; + + if (!rtnl) + rtnl = &our_rtnl; + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, 0); + if (r < 0) + return r; + + r = sd_netlink_message_append_string(message, IFLA_ALT_IFNAME, name); + if (r < 0) + return r; + + r = sd_netlink_call(*rtnl, message, 0, &reply); + if (r == -EINVAL) + return -ENODEV; /* The device doesn't exist */ + if (r < 0) + return r; + + r = sd_rtnl_message_link_get_ifindex(reply, &ifindex); + if (r < 0) + return r; + assert(ifindex > 0); + + if (ret) { + r = sd_netlink_message_read_string_strdup(message, IFLA_IFNAME, ret); + if (r < 0) + return r; + } + + return ifindex; +} + +int rtnl_resolve_ifname(sd_netlink **rtnl, const char *name) { + int r; + + /* Like if_nametoindex, but resolves "alternative names" too. */ + + assert(name); + + r = if_nametoindex(name); + if (r > 0) + return r; + + return rtnl_resolve_link_alternative_name(rtnl, name, NULL); +} + +int rtnl_resolve_interface(sd_netlink **rtnl, const char *name) { + int r; + + /* Like rtnl_resolve_ifname, but resolves interface numbers too. */ + + assert(name); + + r = parse_ifindex(name); + if (r > 0) + return r; + assert(r < 0); + + return rtnl_resolve_ifname(rtnl, name); +} + +int rtnl_resolve_interface_or_warn(sd_netlink **rtnl, const char *name) { + int r; + + r = rtnl_resolve_interface(rtnl, name); + if (r < 0) + return log_error_errno(r, "Failed to resolve interface \"%s\": %m", name); + return r; +} + +int rtnl_get_link_info( + sd_netlink **rtnl, + int ifindex, + unsigned short *ret_iftype, + unsigned *ret_flags, + char **ret_kind, + struct hw_addr_data *ret_hw_addr, + struct hw_addr_data *ret_permanent_hw_addr) { + + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL; + struct hw_addr_data addr = HW_ADDR_NULL, perm_addr = HW_ADDR_NULL; + _cleanup_free_ char *kind = NULL; + unsigned short iftype; + unsigned flags; + int r; + + assert(rtnl); + assert(ifindex > 0); + + if (!ret_iftype && !ret_flags) + return 0; + + if (!*rtnl) { + r = sd_netlink_open(rtnl); + if (r < 0) + return r; + } + + r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex); + if (r < 0) + return r; + + r = sd_netlink_call(*rtnl, message, 0, &reply); + if (r == -EINVAL) + return -ENODEV; /* The device does not exist */ + if (r < 0) + return r; + + if (ret_iftype) { + r = sd_rtnl_message_link_get_type(reply, &iftype); + if (r < 0) + return r; + } + + if (ret_flags) { + r = sd_rtnl_message_link_get_flags(reply, &flags); + if (r < 0) + return r; + } + + if (ret_kind) { + r = sd_netlink_message_enter_container(reply, IFLA_LINKINFO); + if (r >= 0) { + r = sd_netlink_message_read_string_strdup(reply, IFLA_INFO_KIND, &kind); + if (r < 0 && r != -ENODATA) + return r; + + r = sd_netlink_message_exit_container(reply); + if (r < 0) + return r; + } + } + + if (ret_hw_addr) { + r = netlink_message_read_hw_addr(reply, IFLA_ADDRESS, &addr); + if (r < 0 && r != -ENODATA) + return r; + } + + if (ret_permanent_hw_addr) { + r = netlink_message_read_hw_addr(reply, IFLA_PERM_ADDRESS, &perm_addr); + if (r < 0 && r != -ENODATA) + return r; + } + + if (ret_iftype) + *ret_iftype = iftype; + if (ret_flags) + *ret_flags = flags; + if (ret_kind) + *ret_kind = TAKE_PTR(kind); + if (ret_hw_addr) + *ret_hw_addr = addr; + if (ret_permanent_hw_addr) + *ret_permanent_hw_addr = perm_addr; + return 0; +} + +int rtnl_log_parse_error(int r) { + return log_error_errno(r, "Failed to parse netlink message: %m"); +} + +int rtnl_log_create_error(int r) { + return log_error_errno(r, "Failed to create netlink message: %m"); +} + +void rtattr_append_attribute_internal(struct rtattr *rta, unsigned short type, const void *data, size_t data_length) { + size_t padding_length; + uint8_t *padding; + + assert(rta); + assert(!data || data_length > 0); + + /* fill in the attribute */ + rta->rta_type = type; + rta->rta_len = RTA_LENGTH(data_length); + if (data) + /* we don't deal with the case where the user lies about the type + * and gives us too little data (so don't do that) + */ + padding = mempcpy(RTA_DATA(rta), data, data_length); + + else + /* if no data was passed, make sure we still initialize the padding + note that we can have data_length > 0 (used by some containers) */ + padding = RTA_DATA(rta); + + /* make sure also the padding at the end of the message is initialized */ + padding_length = (uint8_t *) rta + RTA_SPACE(data_length) - padding; + memzero(padding, padding_length); +} + +int rtattr_append_attribute(struct rtattr **rta, unsigned short type, const void *data, size_t data_length) { + struct rtattr *new_rta, *sub_rta; + size_t message_length; + + assert(rta); + assert(!data || data_length > 0); + + /* get the new message size (with padding at the end) */ + message_length = RTA_ALIGN(rta ? (*rta)->rta_len : 0) + RTA_SPACE(data_length); + + /* buffer should be smaller than both one page or 8K to be accepted by the kernel */ + if (message_length > MIN(page_size(), 8192UL)) + return -ENOBUFS; + + /* realloc to fit the new attribute */ + new_rta = realloc(*rta, message_length); + if (!new_rta) + return -ENOMEM; + *rta = new_rta; + + /* get pointer to the attribute we are about to add */ + sub_rta = (struct rtattr *) ((uint8_t *) *rta + RTA_ALIGN((*rta)->rta_len)); + + rtattr_append_attribute_internal(sub_rta, type, data, data_length); + + /* update rta_len */ + (*rta)->rta_len = message_length; + + return 0; +} + +MultipathRoute *multipath_route_free(MultipathRoute *m) { + if (!m) + return NULL; + + free(m->ifname); + + return mfree(m); +} + +int multipath_route_dup(const MultipathRoute *m, MultipathRoute **ret) { + _cleanup_(multipath_route_freep) MultipathRoute *n = NULL; + _cleanup_free_ char *ifname = NULL; + + assert(m); + assert(ret); + + if (m->ifname) { + ifname = strdup(m->ifname); + if (!ifname) + return -ENOMEM; + } + + n = new(MultipathRoute, 1); + if (!n) + return -ENOMEM; + + *n = (MultipathRoute) { + .gateway = m->gateway, + .weight = m->weight, + .ifindex = m->ifindex, + .ifname = TAKE_PTR(ifname), + }; + + *ret = TAKE_PTR(n); + + return 0; +} + +int rtattr_read_nexthop(const struct rtnexthop *rtnh, size_t size, int family, OrderedSet **ret) { + _cleanup_ordered_set_free_free_ OrderedSet *set = NULL; + int r; + + assert(rtnh); + assert(IN_SET(family, AF_INET, AF_INET6)); + + if (size < sizeof(struct rtnexthop)) + return -EBADMSG; + + for (; size >= sizeof(struct rtnexthop); ) { + _cleanup_(multipath_route_freep) MultipathRoute *m = NULL; + + if (NLMSG_ALIGN(rtnh->rtnh_len) > size) + return -EBADMSG; + + if (rtnh->rtnh_len < sizeof(struct rtnexthop)) + return -EBADMSG; + + m = new(MultipathRoute, 1); + if (!m) + return -ENOMEM; + + *m = (MultipathRoute) { + .ifindex = rtnh->rtnh_ifindex, + .weight = rtnh->rtnh_hops, + }; + + if (rtnh->rtnh_len > sizeof(struct rtnexthop)) { + size_t len = rtnh->rtnh_len - sizeof(struct rtnexthop); + + for (struct rtattr *attr = RTNH_DATA(rtnh); RTA_OK(attr, len); attr = RTA_NEXT(attr, len)) { + if (attr->rta_type == RTA_GATEWAY) { + if (attr->rta_len != RTA_LENGTH(FAMILY_ADDRESS_SIZE(family))) + return -EBADMSG; + + m->gateway.family = family; + memcpy(&m->gateway.address, RTA_DATA(attr), FAMILY_ADDRESS_SIZE(family)); + break; + } else if (attr->rta_type == RTA_VIA) { + uint16_t gw_family; + + if (family != AF_INET) + return -EINVAL; + + if (attr->rta_len < RTA_LENGTH(sizeof(uint16_t))) + return -EBADMSG; + + gw_family = *(uint16_t *) RTA_DATA(attr); + + if (gw_family != AF_INET6) + return -EBADMSG; + + if (attr->rta_len != RTA_LENGTH(FAMILY_ADDRESS_SIZE(gw_family) + sizeof(gw_family))) + return -EBADMSG; + + memcpy(&m->gateway, RTA_DATA(attr), FAMILY_ADDRESS_SIZE(gw_family) + sizeof(gw_family)); + break; + } + } + } + + r = ordered_set_ensure_put(&set, NULL, m); + if (r < 0) + return r; + + TAKE_PTR(m); + + size -= NLMSG_ALIGN(rtnh->rtnh_len); + rtnh = RTNH_NEXT(rtnh); + } + + if (ret) + *ret = TAKE_PTR(set); + return 0; +} + +bool netlink_pid_changed(sd_netlink *nl) { + /* We don't support people creating an nl connection and + * keeping it around over a fork(). Let's complain. */ + return ASSERT_PTR(nl)->original_pid != getpid_cached(); +} + +static int socket_open(int family) { + int fd; + + fd = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, family); + if (fd < 0) + return -errno; + + return fd_move_above_stdio(fd); +} + +int netlink_open_family(sd_netlink **ret, int family) { + _cleanup_close_ int fd = -1; + int r; + + fd = socket_open(family); + if (fd < 0) + return fd; + + r = sd_netlink_open_fd(ret, fd); + if (r < 0) + return r; + TAKE_FD(fd); + + return 0; +} + +void netlink_seal_message(sd_netlink *nl, sd_netlink_message *m) { + uint32_t picked; + + assert(nl); + assert(!netlink_pid_changed(nl)); + assert(m); + assert(m->hdr); + + /* Avoid collisions with outstanding requests */ + do { + picked = nl->serial; + + /* Don't use seq == 0, as that is used for broadcasts, so we would get confused by replies to + such messages */ + nl->serial = nl->serial == UINT32_MAX ? 1 : nl->serial + 1; + + } while (hashmap_contains(nl->reply_callbacks, UINT32_TO_PTR(picked))); + + m->hdr->nlmsg_seq = picked; + message_seal(m); +} + +static int socket_writev_message(sd_netlink *nl, sd_netlink_message **m, size_t msgcount) { + _cleanup_free_ struct iovec *iovs = NULL; + ssize_t k; + + assert(nl); + assert(m); + assert(msgcount > 0); + + iovs = new(struct iovec, msgcount); + if (!iovs) + return -ENOMEM; + + for (size_t i = 0; i < msgcount; i++) { + assert(m[i]->hdr); + assert(m[i]->hdr->nlmsg_len > 0); + + iovs[i] = IOVEC_MAKE(m[i]->hdr, m[i]->hdr->nlmsg_len); + } + + k = writev(nl->fd, iovs, msgcount); + if (k < 0) + return -errno; + + return k; +} + +int sd_netlink_sendv( + sd_netlink *nl, + sd_netlink_message **messages, + size_t msgcount, + uint32_t **ret_serial) { + + _cleanup_free_ uint32_t *serials = NULL; + int r; + + assert_return(nl, -EINVAL); + assert_return(!netlink_pid_changed(nl), -ECHILD); + assert_return(messages, -EINVAL); + assert_return(msgcount > 0, -EINVAL); + + if (ret_serial) { + serials = new(uint32_t, msgcount); + if (!serials) + return -ENOMEM; + } + + for (size_t i = 0; i < msgcount; i++) { + assert_return(!messages[i]->sealed, -EPERM); + + netlink_seal_message(nl, messages[i]); + if (serials) + serials[i] = message_get_serial(messages[i]); + } + + r = socket_writev_message(nl, messages, msgcount); + if (r < 0) + return r; + + if (ret_serial) + *ret_serial = TAKE_PTR(serials); + + return r; +} |