diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt index 5efae00f6c7fd82f863939ac2e6f2883a52fee09..d2963123eb1ccca8a299486f1eb998f05acf5041 100644 --- a/Documentation/filesystems/nfs/nfsroot.txt +++ b/Documentation/filesystems/nfs/nfsroot.txt @@ -5,6 +5,7 @@ Written 1996 by Gero Kuhlmann Updated 1997 by Martin Mares Updated 2006 by Nico Schottelius Updated 2006 by Horms +Updated 2018 by Chris Novakovic @@ -79,7 +80,7 @@ nfsroot=[:][,] ip=::::::: - : + :: This parameter tells the kernel how to configure IP addresses of devices and also how to set up the IP routing table. It was originally called @@ -110,6 +111,9 @@ ip=::::::: will not be triggered if it is missing and NFS root is not in operation. + Value is exported to /proc/net/pnp with the prefix "bootserver " + (see below). + Default: Determined using autoconfiguration. The address of the autoconfiguration server is used. @@ -123,10 +127,13 @@ ip=::::::: Default: Determined using autoconfiguration. - Name of the client. May be supplied by autoconfiguration, - but its absence will not trigger autoconfiguration. - If specified and DHCP is used, the user provided hostname will - be carried in the DHCP request to hopefully update DNS record. + Name of the client. If a '.' character is present, anything + before the first '.' is used as the client's hostname, and anything + after it is used as its NIS domain name. May be supplied by + autoconfiguration, but its absence will not trigger autoconfiguration. + If specified and DHCP is used, the user-provided hostname (and NIS + domain name, if present) will be carried in the DHCP request; this + may cause a DNS record to be created or updated for the client. Default: Client IP address is used in ASCII notation. @@ -162,12 +169,55 @@ ip=::::::: Default: any - IP address of first nameserver. - Value gets exported by /proc/net/pnp which is often linked - on embedded systems by /etc/resolv.conf. + IP address of primary nameserver. + Value is exported to /proc/net/pnp with the prefix "nameserver " + (see below). + + Default: None if not using autoconfiguration; determined + automatically if using autoconfiguration. + + IP address of secondary nameserver. + See . + + IP address of a Network Time Protocol (NTP) server. + Value is exported to /proc/net/ipconfig/ntp_servers, but is + otherwise unused (see below). + + Default: None if not using autoconfiguration; determined + automatically if using autoconfiguration. + + After configuration (whether manual or automatic) is complete, two files + are created in the following format; lines are omitted if their respective + value is empty following configuration: + + - /proc/net/pnp: + + #PROTO: (depending on configuration method) + domain (if autoconfigured, the DNS domain) + nameserver (primary name server IP) + nameserver (secondary name server IP) + nameserver (tertiary name server IP) + bootserver (NFS server IP) + + - /proc/net/ipconfig/ntp_servers: + + (NTP server IP) + (NTP server IP) + (NTP server IP) + + and (in /proc/net/pnp) and and + (in /proc/net/ipconfig/ntp_servers) are requested during autoconfiguration; + they cannot be specified as part of the "ip=" kernel command line parameter. + + Because the "domain" and "nameserver" options are recognised by DNS + resolvers, /etc/resolv.conf is often linked to /proc/net/pnp on systems + that use an NFS root filesystem. - IP address of second nameserver. - Same as above. + Note that the kernel will not synchronise the system time with any NTP + servers it discovers; this is the responsibility of a user space process + (e.g. an initrd/initramfs script that passes the IP addresses listed in + /proc/net/ipconfig/ntp_servers to an NTP client before mounting the real + root filesystem if it is on NFS). nfsrootdebug diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c index 43f620feb1c45854f847010090fc43a8e810d4ef..d839d74853fc275ae15a22a40273855de5da5c09 100644 --- a/net/ipv4/ipconfig.c +++ b/net/ipv4/ipconfig.c @@ -28,6 +28,9 @@ * * Multiple Nameservers in /proc/net/pnp * -- Josef Siemes , Aug 2002 + * + * NTP servers in /proc/net/ipconfig/ntp_servers + * -- Chris Novakovic , April 2018 */ #include @@ -93,6 +96,7 @@ #define CONF_TIMEOUT_MAX (HZ*30) /* Maximum allowed timeout */ #define CONF_NAMESERVERS_MAX 3 /* Maximum number of nameservers - '3' from resolv.h */ +#define CONF_NTP_SERVERS_MAX 3 /* Maximum number of NTP servers */ #define NONE cpu_to_be32(INADDR_NONE) #define ANY cpu_to_be32(INADDR_ANY) @@ -152,12 +156,16 @@ static int ic_proto_used; /* Protocol used, if any */ #define ic_proto_used 0 #endif static __be32 ic_nameservers[CONF_NAMESERVERS_MAX]; /* DNS Server IP addresses */ +static __be32 ic_ntp_servers[CONF_NTP_SERVERS_MAX]; /* NTP server IP addresses */ static u8 ic_domain[64]; /* DNS (not NIS) domain name */ /* * Private state. */ +/* proc_dir_entry for /proc/net/ipconfig */ +static struct proc_dir_entry *ipconfig_dir; + /* Name of user-selected boot device */ static char user_dev_name[IFNAMSIZ] __initdata = { 0, }; @@ -576,6 +584,15 @@ static inline void __init ic_nameservers_predef(void) ic_nameservers[i] = NONE; } +/* Predefine NTP servers */ +static inline void __init ic_ntp_servers_predef(void) +{ + int i; + + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) + ic_ntp_servers[i] = NONE; +} + /* * DHCP/BOOTP support. */ @@ -671,6 +688,7 @@ ic_dhcp_init_options(u8 *options, struct ic_device *d) 17, /* Boot path */ 26, /* MTU */ 40, /* NIS domain name */ + 42, /* NTP servers */ }; *e++ = 55; /* Parameter request list */ @@ -721,9 +739,11 @@ static void __init ic_bootp_init_ext(u8 *e) *e++ = 3; /* Default gateway request */ *e++ = 4; e += 4; - *e++ = 5; /* Name server request */ - *e++ = 8; - e += 8; +#if CONF_NAMESERVERS_MAX > 0 + *e++ = 6; /* (DNS) name server request */ + *e++ = 4 * CONF_NAMESERVERS_MAX; + e += 4 * CONF_NAMESERVERS_MAX; +#endif *e++ = 12; /* Host name request */ *e++ = 32; e += 32; @@ -748,7 +768,13 @@ static void __init ic_bootp_init_ext(u8 *e) */ static inline void __init ic_bootp_init(void) { + /* Re-initialise all name servers and NTP servers to NONE, in case any + * were set via the "ip=" or "nfsaddrs=" kernel command line parameters: + * any IP addresses specified there will already have been decoded but + * are no longer needed + */ ic_nameservers_predef(); + ic_ntp_servers_predef(); dev_add_pack(&bootp_packet_type); } @@ -912,6 +938,15 @@ static void __init ic_do_bootp_ext(u8 *ext) ic_bootp_string(utsname()->domainname, ext+1, *ext, __NEW_UTS_LEN); break; + case 42: /* NTP servers */ + servers = *ext / 4; + if (servers > CONF_NTP_SERVERS_MAX) + servers = CONF_NTP_SERVERS_MAX; + for (i = 0; i < servers; i++) { + if (ic_ntp_servers[i] == NONE) + memcpy(&ic_ntp_servers[i], ext+1+4*i, 4); + } + break; } } @@ -1258,6 +1293,7 @@ static int __init ic_dynamic(void) #ifdef CONFIG_PROC_FS +/* Name servers: */ static int pnp_seq_show(struct seq_file *seq, void *v) { int i; @@ -1294,6 +1330,62 @@ static const struct file_operations pnp_seq_fops = { .llseek = seq_lseek, .release = single_release, }; + +/* Create the /proc/net/ipconfig directory */ +static int __init ipconfig_proc_net_init(void) +{ + ipconfig_dir = proc_net_mkdir(&init_net, "ipconfig", init_net.proc_net); + if (!ipconfig_dir) + return -ENOMEM; + + return 0; +} + +/* Create a new file under /proc/net/ipconfig */ +static int ipconfig_proc_net_create(const char *name, + const struct file_operations *fops) +{ + char *pname; + struct proc_dir_entry *p; + + if (!ipconfig_dir) + return -ENOMEM; + + pname = kasprintf(GFP_KERNEL, "%s%s", "ipconfig/", name); + if (!pname) + return -ENOMEM; + + p = proc_create(pname, 0444, init_net.proc_net, fops); + kfree(pname); + if (!p) + return -ENOMEM; + + return 0; +} + +/* Write NTP server IP addresses to /proc/net/ipconfig/ntp_servers */ +static int ntp_servers_seq_show(struct seq_file *seq, void *v) +{ + int i; + + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) { + if (ic_ntp_servers[i] != NONE) + seq_printf(seq, "%pI4\n", &ic_ntp_servers[i]); + } + return 0; +} + +static int ntp_servers_seq_open(struct inode *inode, struct file *file) +{ + return single_open(file, ntp_servers_seq_show, NULL); +} + +static const struct file_operations ntp_servers_seq_fops = { + .open = ntp_servers_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; #endif /* CONFIG_PROC_FS */ /* @@ -1368,8 +1460,20 @@ static int __init ip_auto_config(void) int err; unsigned int i; + /* Initialise all name servers and NTP servers to NONE (but only if the + * "ip=" or "nfsaddrs=" kernel command line parameters weren't decoded, + * otherwise we'll overwrite the IP addresses specified there) + */ + if (ic_set_manually == 0) { + ic_nameservers_predef(); + ic_ntp_servers_predef(); + } + #ifdef CONFIG_PROC_FS proc_create("pnp", 0444, init_net.proc_net, &pnp_seq_fops); + + if (ipconfig_proc_net_init() == 0) + ipconfig_proc_net_create("ntp_servers", &ntp_servers_seq_fops); #endif /* CONFIG_PROC_FS */ if (!ic_enable) @@ -1481,16 +1585,32 @@ static int __init ip_auto_config(void) &ic_servaddr, &root_server_addr, root_server_path); if (ic_dev_mtu) pr_cont(", mtu=%d", ic_dev_mtu); - for (i = 0; i < CONF_NAMESERVERS_MAX; i++) + /* Name servers (if any): */ + for (i = 0; i < CONF_NAMESERVERS_MAX; i++) { if (ic_nameservers[i] != NONE) { - pr_cont(" nameserver%u=%pI4", - i, &ic_nameservers[i]); - break; + if (i == 0) + pr_info(" nameserver%u=%pI4", + i, &ic_nameservers[i]); + else + pr_cont(", nameserver%u=%pI4", + i, &ic_nameservers[i]); } - for (i++; i < CONF_NAMESERVERS_MAX; i++) - if (ic_nameservers[i] != NONE) - pr_cont(", nameserver%u=%pI4", i, &ic_nameservers[i]); - pr_cont("\n"); + if (i + 1 == CONF_NAMESERVERS_MAX) + pr_cont("\n"); + } + /* NTP servers (if any): */ + for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) { + if (ic_ntp_servers[i] != NONE) { + if (i == 0) + pr_info(" ntpserver%u=%pI4", + i, &ic_ntp_servers[i]); + else + pr_cont(", ntpserver%u=%pI4", + i, &ic_ntp_servers[i]); + } + if (i + 1 == CONF_NTP_SERVERS_MAX) + pr_cont("\n"); + } #endif /* !SILENT */ /* @@ -1588,7 +1708,9 @@ static int __init ip_auto_config_setup(char *addrs) return 1; } + /* Initialise all name servers and NTP servers to NONE */ ic_nameservers_predef(); + ic_ntp_servers_predef(); /* Parse string for static IP assignment. */ ip = addrs; @@ -1647,6 +1769,13 @@ static int __init ip_auto_config_setup(char *addrs) ic_nameservers[1] = NONE; } break; + case 9: + if (CONF_NTP_SERVERS_MAX >= 1) { + ic_ntp_servers[0] = in_aton(ip); + if (ic_ntp_servers[0] == ANY) + ic_ntp_servers[0] = NONE; + } + break; } } ip = cp;