diff --git a/zebra/ge_netlink.c b/zebra/ge_netlink.c new file mode 100644 index 0000000000..6fce1f9aa5 --- /dev/null +++ b/zebra/ge_netlink.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Generic Netlink functions. + * Copyright (C) 2022, Carmine Scarpitta + */ + +#include + +#ifdef HAVE_NETLINK + +/* The following definition is to workaround an issue in the Linux kernel + * header files with redefinition of 'struct in6_addr' in both + * netinet/in.h and linux/in6.h. + * Reference - https://sourceware.org/ml/libc-alpha/2013-01/msg00599.html + */ +#define _LINUX_IN6_H + +#include +#include +#include + +#include "lib/ns.h" +#include "zebra/ge_netlink.h" +#include "zebra/debug.h" +#include "zebra/kernel_netlink.h" + + +/* + * Numeric family identifier used to configure SRv6 internal parameters through Generic Netlink. + */ +static int16_t seg6_genl_family = -1; + +static int genl_parse_getfamily(struct nlmsghdr *h, ns_id_t ns_id, int startup) +{ + int len; + struct rtattr *tb[CTRL_ATTR_MAX + 1]; + struct genlmsghdr *ghdr = NLMSG_DATA(h); + struct rtattr *attrs; + const char *family; + + if (h->nlmsg_type != GENL_ID_CTRL) { + zlog_err( + "Not a controller message, nlmsg_len=%d nlmsg_type=0x%x", + h->nlmsg_len, h->nlmsg_type); + return 0; + } + + len = h->nlmsg_len - NLMSG_LENGTH(GENL_HDRLEN); + if (len < 0) { + zlog_err( + "Message received from netlink is of a broken size %d %zu", + h->nlmsg_len, (size_t)NLMSG_LENGTH(GENL_HDRLEN)); + return -1; + } + + if (ghdr->cmd != CTRL_CMD_NEWFAMILY) { + zlog_err("Unknown controller command %d", ghdr->cmd); + return -1; + } + + attrs = (struct rtattr *)((char *)ghdr + GENL_HDRLEN); + netlink_parse_rtattr(tb, CTRL_ATTR_MAX, attrs, len); + + if (tb[CTRL_ATTR_FAMILY_ID] == NULL) { + zlog_err("Missing family id TLV"); + return -1; + } + + if (tb[CTRL_ATTR_FAMILY_NAME] == NULL) { + zlog_err("Missing family name TLV"); + return -1; + } + + family = (char *)RTA_DATA(tb[CTRL_ATTR_FAMILY_NAME]); + + if (strmatch(family, "SEG6")) + seg6_genl_family = + *(int16_t *)RTA_DATA(tb[CTRL_ATTR_FAMILY_ID]); + else { + if (IS_ZEBRA_DEBUG_KERNEL) + zlog_err("Unsupported Generic Netlink family '%s'", + family); + return -1; + } + + return 0; +} + +int genl_resolve_family(const char *family) +{ + struct zebra_ns *zns; + struct genl_request req; + + memset(&req, 0, sizeof(req)); + + zns = zebra_ns_lookup(NS_DEFAULT); + + req.n.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN); + req.n.nlmsg_flags = NLM_F_REQUEST; + req.n.nlmsg_type = GENL_ID_CTRL; + + req.n.nlmsg_pid = zns->ge_netlink_cmd.snl.nl_pid; + + req.g.cmd = CTRL_CMD_GETFAMILY; + req.g.version = 0; + + if (!nl_attr_put(&req.n, sizeof(req), CTRL_ATTR_FAMILY_NAME, family, + strlen(family) + 1)) + return -1; + + return ge_netlink_talk(genl_parse_getfamily, &req.n, zns, false); +} + +void ge_netlink_init(struct zebra_ns *zns) +{ + if (zns->ge_netlink_cmd.sock < 0) + return; + + /* + * Resolves the 'seg6' Generic Netlink family name to the corresponding numeric family identifier. + * This will give us the numeric family identifier required to send 'seg6' commands to the kernel + * over the Generic Netlink socket. 'seg6' commands are used to configure SRv6 internal parameters + * such as the address to use as source for encapsulated packets. + */ + if (genl_resolve_family("SEG6")) + zlog_warn( + "Kernel does not support 'SEG6' Generic Netlink family. Any attempt to set the encapsulation parameters under the SRv6 configuration will fail"); +} + +#endif /* HAVE_NETLINK */ diff --git a/zebra/ge_netlink.h b/zebra/ge_netlink.h new file mode 100644 index 0000000000..402a29b66e --- /dev/null +++ b/zebra/ge_netlink.h @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Header file exported by ge_netlink.c to zebra. + * Copyright (C) 2022, Carmine Scarpitta + */ + +#ifndef _ZEBRA_GE_NETLINK_H +#define _ZEBRA_GE_NETLINK_H + +#include "zebra_dplane.h" + +#ifdef HAVE_NETLINK + +#include + +#ifdef __cplusplus +extern "C" { +#endif + +/* Generic Netlink request message */ +struct genl_request { + struct nlmsghdr n; + struct genlmsghdr g; + char buf[1024]; +}; + +extern int genl_resolve_family(const char *family); +extern void ge_netlink_init(struct zebra_ns *zns); + +#ifdef __cplusplus +} +#endif + +#endif /* HAVE_NETLINK */ + +#endif /* _ZEBRA_GE_NETLINK_H */ diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c index 424794135d..5aa509d116 100644 --- a/zebra/kernel_netlink.c +++ b/zebra/kernel_netlink.c @@ -38,6 +38,7 @@ #include "zebra/tc_netlink.h" #include "zebra/netconf_netlink.h" #include "zebra/zebra_errors.h" +#include "zebra/ge_netlink.h" #ifndef SO_RCVBUFFORCE #define SO_RCVBUFFORCE (33) @@ -1958,6 +1959,8 @@ void kernel_init(struct zebra_ns *zns) &zns->t_netlink); rt_netlink_init(); + + ge_netlink_init(); } /* Helper to clean up an nlsock */ diff --git a/zebra/subdir.am b/zebra/subdir.am index b3bd9be9c2..a59515d3a8 100644 --- a/zebra/subdir.am +++ b/zebra/subdir.am @@ -52,6 +52,7 @@ zebra_zebra_SOURCES = \ zebra/redistribute.c \ zebra/router-id.c \ zebra/rt_netlink.c \ + zebra/ge_netlink.c \ zebra/rt_socket.c \ zebra/rtadv.c \ zebra/rtread_netlink.c \ @@ -144,6 +145,7 @@ noinst_HEADERS += \ zebra/router-id.h \ zebra/rt.h \ zebra/rt_netlink.h \ + zebra/ge_netlink.h \ zebra/rtadv.h \ zebra/rule_netlink.h \ zebra/table_manager.h \