From 35ff74676b54b1cae5a6324d2517568393fedbc8 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Wed, 28 Nov 2007 19:23:12 +0000 Subject: [PATCH] dhcpc: let server know we don't like oversized packets. add TODO comment --- networking/udhcp/Config.in | 1 + networking/udhcp/clientpacket.c | 3 ++ networking/udhcp/files.c | 6 +-- networking/udhcp/options.c | 68 ++++++++++++++++++--------------- networking/udhcp/options.h | 4 +- networking/udhcp/script.c | 23 +++++------ 6 files changed, 58 insertions(+), 47 deletions(-) diff --git a/networking/udhcp/Config.in b/networking/udhcp/Config.in index 1aef69ba7..242a9f3b8 100644 --- a/networking/udhcp/Config.in +++ b/networking/udhcp/Config.in @@ -104,3 +104,4 @@ config UDHCPC_SLACK_FOR_BUGGY_SERVERS seems to confuse maximum allowed UDP packet size with maximum size of entire IP packet, and sends packets which are 28 bytes too large. + Seednet (ISP) VDSL: sends packets 2 bytes too big. diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c index 4a5c627f4..406fe340a 100644 --- a/networking/udhcp/clientpacket.c +++ b/networking/udhcp/clientpacket.c @@ -96,6 +96,9 @@ int send_discover(uint32_t xid, uint32_t requested) if (requested) add_simple_option(packet.options, DHCP_REQUESTED_IP, requested); + /* Explicitly saying that we want RFC-compliant packets helps + * some buggy DHCP servers to NOT send bigger packets */ + add_simple_option(packet.options, DHCP_MAX_SIZE, htons(576)); add_requests(&packet); bb_info_msg("Sending discover..."); return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST, diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c index 59a5e4ab2..5026598d7 100644 --- a/networking/udhcp/files.c +++ b/networking/udhcp/files.c @@ -90,7 +90,7 @@ static void attach_option(struct option_set **opt_list, existing = find_option(*opt_list, option->code); if (!existing) { - DEBUG("Attaching option %s to list", option->name); + DEBUG("Attaching option %02x to list", option->code); #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035) @@ -119,7 +119,7 @@ static void attach_option(struct option_set **opt_list, } /* add it to an existing option */ - DEBUG("Attaching option %s to existing member of list", option->name); + DEBUG("Attaching option %02x to existing member of list", option->code); if (option->flags & OPTION_LIST) { #if ENABLE_FEATURE_RFC3397 if ((option->flags & TYPE_MASK) == OPTION_STR1035) @@ -170,7 +170,7 @@ static int read_opt(const char *const_line, void *arg) while (1) { if (!option->code) return 0; - if (!strcasecmp(option->name, opt)) + if (!strcasecmp(option->opt_name, opt)) break; option++; } diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c index 6744e2ad0..ffc0ed127 100644 --- a/networking/udhcp/options.c +++ b/networking/udhcp/options.c @@ -9,37 +9,42 @@ #include "options.h" -/* supported options are easily added here */ +/* Supported options are easily added here */ const struct dhcp_option dhcp_options[] = { - /* name[12] flags code */ - {"subnet", OPTION_IP | OPTION_REQ, 0x01}, - {"timezone", OPTION_S32, 0x02}, - {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03}, - {"timesvr", OPTION_IP | OPTION_LIST, 0x04}, - {"namesvr", OPTION_IP | OPTION_LIST, 0x05}, - {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06}, - {"logsvr", OPTION_IP | OPTION_LIST, 0x07}, - {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08}, - {"lprsvr", OPTION_IP | OPTION_LIST, 0x09}, - {"hostname", OPTION_STRING | OPTION_REQ, 0x0c}, - {"bootsize", OPTION_U16, 0x0d}, - {"domain", OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f}, - {"swapsvr", OPTION_IP, 0x10}, - {"rootpath", OPTION_STRING, 0x11}, - {"ipttl", OPTION_U8, 0x17}, - {"mtu", OPTION_U16, 0x1a}, - {"broadcast", OPTION_IP | OPTION_REQ, 0x1c}, - {"nisdomain", OPTION_STRING | OPTION_REQ, 0x28}, - {"nissrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x29}, - {"ntpsrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a}, - {"wins", OPTION_IP | OPTION_LIST, 0x2c}, - {"requestip", OPTION_IP, 0x32}, - {"lease", OPTION_U32, 0x33}, - {"dhcptype", OPTION_U8, 0x35}, - {"serverid", OPTION_IP, 0x36}, - {"message", OPTION_STRING, 0x38}, - {"vendorclass", OPTION_STRING, 0x3C}, - {"clientid", OPTION_STRING, 0x3D}, + /* opt_name[12] flags code */ + {"subnet", OPTION_IP | OPTION_REQ, 0x01}, /* DHCP_SUBNET */ + {"timezone", OPTION_S32, 0x02}, /* DHCP_TIME_OFFSET */ + {"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03}, /* DHCP_ROUTER */ + {"timesvr", OPTION_IP | OPTION_LIST, 0x04}, /* DHCP_TIME_SERVER */ + {"namesvr", OPTION_IP | OPTION_LIST, 0x05}, /* DHCP_NAME_SERVER */ + {"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06}, /* DHCP_DNS_SERVER */ + {"logsvr", OPTION_IP | OPTION_LIST, 0x07}, /* DHCP_LOG_SERVER */ + {"cookiesvr", OPTION_IP | OPTION_LIST, 0x08}, /* DHCP_COOKIE_SERVER */ + {"lprsvr", OPTION_IP | OPTION_LIST, 0x09}, /* DHCP_LPR_SERVER */ + {"hostname", OPTION_STRING | OPTION_REQ, 0x0c}, /* DHCP_HOST_NAME */ + {"bootsize", OPTION_U16, 0x0d}, /* DHCP_BOOT_SIZE */ + {"domain", OPTION_STRING | OPTION_LIST | OPTION_REQ, 0x0f}, /* DHCP_DOMAIN_NAME */ + {"swapsvr", OPTION_IP, 0x10}, /* DHCP_SWAP_SERVER */ + {"rootpath", OPTION_STRING, 0x11}, /* DHCP_ROOT_PATH */ + {"ipttl", OPTION_U8, 0x17}, /* DHCP_IP_TTL */ + {"mtu", OPTION_U16, 0x1a}, /* DHCP_MTU */ + {"broadcast", OPTION_IP | OPTION_REQ, 0x1c}, /* DHCP_BROADCAST */ + {"nisdomain", OPTION_STRING | OPTION_REQ, 0x28}, /* DHCP_NTP_SERVER */ + {"nissrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x29}, /* DHCP_WINS_SERVER */ + {"ntpsrv", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a}, /* DHCP_REQUESTED_IP */ + {"wins", OPTION_IP | OPTION_LIST, 0x2c}, /* DHCP_LEASE_TIME */ + {"requestip", OPTION_IP, 0x32}, /* DHCP_OPTION_OVER */ + {"lease", OPTION_U32, 0x33}, /* DHCP_MESSAGE_TYPE */ + {"dhcptype", OPTION_U8, 0x35}, /* DHCP_SERVER_ID */ + {"serverid", OPTION_IP, 0x36}, /* DHCP_PARAM_REQ */ + {"message", OPTION_STRING, 0x38}, /* DHCP_MESSAGE */ +// TODO: 1) some options should not be parsed & passed to script - +// maxsize sure should not, since it cannot appear in server responses! +// grep for opt_name is fix the mess. +// 2) Using fixed-sized char[] vector wastes space. + {"maxsize", OPTION_U16, 0x39}, /* DHCP_MAX_SIZE */ + {"vendorclass", OPTION_STRING, 0x3C}, /* DHCP_VENDOR */ + {"clientid", OPTION_STRING, 0x3D}, /* DHCP_CLIENT_ID */ {"tftp", OPTION_STRING, 0x42}, {"bootfile", OPTION_STRING, 0x43}, {"userclass", OPTION_STRING, 0x4D}, @@ -48,9 +53,10 @@ const struct dhcp_option dhcp_options[] = { #endif /* MSIE's "Web Proxy Autodiscovery Protocol" support */ {"wpad", OPTION_STRING, 0xfc}, - {"", 0x00, 0x00} + {} /* zero-padded terminating entry */ }; + /* Lengths of the different option types */ const unsigned char option_lengths[] ALIGN1 = { [OPTION_IP] = 4, diff --git a/networking/udhcp/options.h b/networking/udhcp/options.h index 33a968ce9..4bf73a17e 100644 --- a/networking/udhcp/options.h +++ b/networking/udhcp/options.h @@ -33,6 +33,7 @@ enum { #define DHCP_MAGIC 0x63825363 + /* DHCP option codes (partial list) */ #define DHCP_PADDING 0x00 #define DHCP_SUBNET 0x01 @@ -67,7 +68,6 @@ enum { #define DHCP_VENDOR 0x3c #define DHCP_CLIENT_ID 0x3d #define DHCP_FQDN 0x51 - #define DHCP_END 0xFF @@ -98,7 +98,7 @@ enum { #define OPT_DATA 2 struct dhcp_option { - char name[12]; + char opt_name[12]; char flags; uint8_t code; }; diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c index 68de358e5..33d96e687 100644 --- a/networking/udhcp/script.c +++ b/networking/udhcp/script.c @@ -44,14 +44,15 @@ static int sprintip(char *dest, const char *pre, const uint8_t *ip) /* really simple implementation, just count the bits */ -static int mton(struct in_addr *mask) +static int mton(uint32_t mask) { - int i; - unsigned long bits = ntohl(mask->s_addr); - /* too bad one can't check the carry bit, etc in c bit - * shifting */ - for (i = 0; i < 32 && !((bits >> i) & 1); i++); - return 32 - i; + int i = 0; + mask = ntohl(mask); /* 111110000-like bit pattern */ + while (mask) { + i++; + mask <<= 1; + } + return i; } @@ -69,8 +70,8 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p) type = type_p->flags & TYPE_MASK; optlen = option_lengths[type]; - dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->name) + 2); - dest += sprintf(ret, "%s=", type_p->name); + dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->opt_name) + 2); + dest += sprintf(ret, "%s=", type_p->opt_name); for (;;) { switch (type) { @@ -133,7 +134,6 @@ static char **fill_envp(struct dhcpMessage *packet) char **envp; char *var; uint8_t *temp; - struct in_addr subnet; char over = 0; if (packet) { @@ -179,8 +179,9 @@ static char **fill_envp(struct dhcpMessage *packet) /* Fill in a subnet bits option for things like /24 */ if (dhcp_options[i].code == DHCP_SUBNET) { + uint32_t subnet; memcpy(&subnet, temp, 4); - envp[j++] = xasprintf("mask=%d", mton(&subnet)); + envp[j++] = xasprintf("mask=%d", mton(subnet)); } } if (packet->siaddr) { -- 2.25.1