network-generator: introduce new tool systemd-network-generator

The new tool parses dracut's command line options and generates
relevant .network, .netdev, and .link files.

meson.build

@@ -2710,6 +2710,14 @@ if conf.get('ENABLE_NETWORKD') == 1
                    install : true,
                    install_dir : rootbindir)
         public_programs += exe
+
+        executable('systemd-network-generator',
+                   network_generator_sources,
+                   include_directories : includes,
+                   link_with : [libshared],
+                   install_rpath : rootlibexecdir,
+                   install : true,
+                   install_dir : rootlibexecdir)
 endif
 
 executable('systemd-sulogin-shell',

src/network/generator/main.c

@@ -0,0 +1,206 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <getopt.h>
+
+#include "fd-util.h"
+#include "generator.h"
+#include "macro.h"
+#include "main-func.h"
+#include "mkdir.h"
+#include "network-generator.h"
+#include "path-util.h"
+#include "proc-cmdline.h"
+
+#define NETWORKD_UNIT_DIRECTORY "/run/systemd/network"
+
+static const char *arg_root = NULL;
+
+static int network_save(Network *network, const char *dest_dir) {
+        _cleanup_free_ char *filename = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(network);
+
+        r = asprintf(&filename, "%s-initrd-%s.network",
+                     isempty(network->ifname) ? "99" : "98",
+                     isempty(network->ifname) ? "default" : network->ifname);
+        if (r < 0)
+                return log_oom();
+
+        r = generator_open_unit_file(dest_dir, "kernel command line", filename, &f);
+        if (r < 0)
+                return r;
+
+        network_dump(network, f);
+
+        return 0;
+}
+
+static int netdev_save(NetDev *netdev, const char *dest_dir) {
+        _cleanup_free_ char *filename = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(netdev);
+
+        r = asprintf(&filename, "98-initrd-%s.netdev",
+                     netdev->ifname);
+        if (r < 0)
+                return log_oom();
+
+        r = generator_open_unit_file(dest_dir, "kernel command line", filename, &f);
+        if (r < 0)
+                return r;
+
+        netdev_dump(netdev, f);
+
+        return 0;
+}
+
+static int link_save(Link *link, const char *dest_dir) {
+        _cleanup_free_ char *filename = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(link);
+
+        r = asprintf(&filename, "98-initrd-%s.link",
+                     link->ifname);
+        if (r < 0)
+                return log_oom();
+
+        r = generator_open_unit_file(dest_dir, "kernel command line", filename, &f);
+        if (r < 0)
+                return r;
+
+        link_dump(link, f);
+
+        return 0;
+}
+
+static int context_save(Context *context) {
+        Network *network;
+        NetDev *netdev;
+        Link *link;
+        Iterator i;
+        int k, r = 0;
+        const char *p;
+
+        p = prefix_roota(arg_root, NETWORKD_UNIT_DIRECTORY);
+
+        r = mkdir_p(p, 0755);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create directory " NETWORKD_UNIT_DIRECTORY ": %m");
+
+        HASHMAP_FOREACH(network, context->networks_by_name, i) {
+                k = network_save(network, p);
+                if (k < 0 && r >= 0)
+                        r = k;
+        }
+
+        HASHMAP_FOREACH(netdev, context->netdevs_by_name, i) {
+                k = netdev_save(netdev, p);
+                if (k < 0 && r >= 0)
+                        r = k;
+        }
+
+        HASHMAP_FOREACH(link, context->links_by_name, i) {
+                k = link_save(link, p);
+                if (k < 0 && r >= 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int help(void) {
+        printf("%s [OPTIONS...] [-- KERNEL_CMDLINE]\n"
+               "  -h --help                       Show this help\n"
+               "     --version                    Show package version\n"
+               , program_invocation_short_name
+               );
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_ROOT,
+        };
+        static const struct option options[] = {
+                { "help",               no_argument,       NULL, 'h'                    },
+                { "version",            no_argument,       NULL, ARG_VERSION            },
+                { "root",               required_argument, NULL, ARG_ROOT               },
+                {},
+        };
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+
+                switch (c) {
+
+                case 'h':
+                        return help();
+
+                case ARG_VERSION:
+                        return version();
+
+                case ARG_ROOT:
+                        arg_root = optarg;
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        return 1;
+}
+
+static int run(int argc, char *argv[]) {
+        _cleanup_(context_clear) Context context = {};
+        int i, r;
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r;
+
+        if (optind >= argc) {
+                r = proc_cmdline_parse(parse_cmdline_item, &context, 0);
+                if (r < 0)
+                        return log_warning_errno(r, "Failed to parse kernel command line: %m");
+        } else {
+                for (i = optind; i < argc; i++) {
+                        _cleanup_free_ char *word = NULL;
+                        char *value;
+
+                        word = strdup(argv[i]);
+                        if (!word)
+                                return log_oom();
+
+                        value = strchr(word, '=');
+                        if (value)
+                                *(value++) = 0;
+
+                        r = parse_cmdline_item(word, value, &context);
+                        if (r < 0)
+                                return log_warning_errno(r, "Failed to parse command line \"%s%s%s\": %m",
+                                                         word, value ? "=" : "", strempty(value));
+                }
+        }
+
+        r = context_merge_networks(&context);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to merge multiple command line options: %m");
+
+        return context_save(&context);
+}
+
+DEFINE_MAIN_FUNCTION(run);

src/network/generator/network-generator.h

@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+#pragma once
+
+#include <net/ethernet.h>
+#include <stdio.h>
+
+#include "hashmap.h"
+#include "in-addr-util.h"
+#include "list.h"
+
+typedef enum DHCPType {
+        DHCP_TYPE_NONE,
+        DHCP_TYPE_OFF,
+        DHCP_TYPE_ON,
+        DHCP_TYPE_ANY,
+        DHCP_TYPE_DHCP,
+        DHCP_TYPE_DHCP6,
+        DHCP_TYPE_AUTO6,
+        DHCP_TYPE_EITHER6,
+        DHCP_TYPE_IBFT,
+        _DHCP_TYPE_MAX,
+        _DHCP_TYPE_INVALID = -1,
+} DHCPType;
+
+typedef struct Address Address;
+typedef struct Link Link;
+typedef struct NetDev NetDev;
+typedef struct Network Network;
+typedef struct Route Route;
+typedef struct Context Context;
+
+struct Address {
+        Network *network;
+
+        union in_addr_union address, peer;
+        unsigned char prefixlen;
+        int family;
+
+        LIST_FIELDS(Address, addresses);
+};
+
+struct Route {
+        Network *network;
+
+        union in_addr_union dest, gateway;
+        unsigned char prefixlen;
+        int family;
+
+        LIST_FIELDS(Route, routes);
+};
+
+struct Network {
+        /* [Match] */
+        char *ifname;
+
+        /* [Link] */
+        struct ether_addr mac;
+        uint32_t mtu;
+
+        /* [Network] */
+        DHCPType dhcp_type;
+        char **dns;
+        char *vlan;
+        char *bridge;
+        char *bond;
+
+        /* [DHCP] */
+        char *hostname;
+        int dhcp_use_dns;
+
+        LIST_HEAD(Address, addresses);
+        LIST_HEAD(Route, routes);
+};
+
+struct NetDev {
+        /* [NetDev] */
+        char *ifname;
+        char *kind;
+        uint32_t mtu;
+};
+
+struct Link {
+        /* [Match] */
+        char *ifname;
+        struct ether_addr mac;
+};
+
+typedef struct Context {
+        Hashmap *networks_by_name;
+        Hashmap *netdevs_by_name;
+        Hashmap *links_by_name;
+} Context;
+
+int parse_cmdline_item(const char *key, const char *value, void *data);
+int context_merge_networks(Context *context);
+void context_clear(Context *context);
+
+Network *network_get(Context *context, const char *ifname);
+void network_dump(Network *network, FILE *f);
+int network_format(Network *network, char **ret);
+
+NetDev *netdev_get(Context *context, const char *ifname);
+void netdev_dump(NetDev *netdev, FILE *f);
+int netdev_format(NetDev *netdev, char **ret);
+
+Link *link_get(Context *context, const char *ifname);
+void link_dump(Link *link, FILE *f);
+int link_format(Link *link, char **ret);

src/network/meson.build

@@ -114,6 +114,12 @@ systemd_networkd_wait_online_sources = files('''
 
 networkctl_sources = files('networkctl.c')
 
+network_generator_sources = files('''
+        generator/main.c
+        generator/network-generator.c
+        generator/network-generator.h
+'''.split())
+
 network_include_dir = include_directories('.')
 
 if conf.get('ENABLE_NETWORKD') == 1