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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2011-03-19 21:04:13 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2011-03-19 21:04:13 +0000 |
commit | 7cc856ea2f1808e98387ea66537ecbc6c3de2f88 (patch) | |
tree | 673b6eef191373f0607e5b9a9f79ad390e9bb970 /apps/netutils/resolv/resolv.c | |
parent | 7267882ebd0a6aa79cf88b7f42675804eaff1bcf (diff) | |
download | nuttx-7cc856ea2f1808e98387ea66537ecbc6c3de2f88.tar.gz nuttx-7cc856ea2f1808e98387ea66537ecbc6c3de2f88.tar.bz2 nuttx-7cc856ea2f1808e98387ea66537ecbc6c3de2f88.zip |
Move nuttx/netutils to apps/netutils
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3401 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'apps/netutils/resolv/resolv.c')
-rw-r--r-- | apps/netutils/resolv/resolv.c | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/apps/netutils/resolv/resolv.c b/apps/netutils/resolv/resolv.c new file mode 100644 index 000000000..db9e00085 --- /dev/null +++ b/apps/netutils/resolv/resolv.c @@ -0,0 +1,440 @@ +/**************************************************************************** + * uip-resolv.c + * DNS host name to IP address resolver. + * + * The uIP DNS resolver functions are used to lookup a hostname and + * map it to a numerical IP address. It maintains a list of resolved + * hostnames that can be queried with the resolv_lookup() + * function. New hostnames can be resolved using the resolv_query() + * function. + * + * When a hostname has been resolved (or found to be non-existant), + * the resolver code calls a callback function called resolv_found() + * that must be implemented by the module that uses the resolver. + * + * Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Based heavily on portions of uIP: + * + * Author: Adam Dunkels <adam@dunkels.com> + * Copyright (c) 2002-2003, Adam Dunkels. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS + * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE + * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdint.h> +#include <string.h> +#include <unistd.h> +#include <time.h> +#include <errno.h> +#include <debug.h> + +#include <sys/socket.h> +#include <arpa/inet.h> + +#include <apps/netutils/resolv.h> + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +#ifndef CONFIG_NET_RESOLV_ENTRIES +#define RESOLV_ENTRIES 4 +#else /* CONFIG_NET_RESOLV_ENTRIES */ +#define RESOLV_ENTRIES CONFIG_NET_RESOLV_ENTRIES +#endif /* CONFIG_NET_RESOLV_ENTRIES */ + +#ifndef NULL +#define NULL (void *)0 +#endif /* NULL */ + +/* The maximum number of retries when asking for a name */ + +#define MAX_RETRIES 8 + +#define DNS_FLAG1_RESPONSE 0x80 +#define DNS_FLAG1_OPCODE_STATUS 0x10 +#define DNS_FLAG1_OPCODE_INVERSE 0x08 +#define DNS_FLAG1_OPCODE_STANDARD 0x00 +#define DNS_FLAG1_AUTHORATIVE 0x04 +#define DNS_FLAG1_TRUNC 0x02 +#define DNS_FLAG1_RD 0x01 +#define DNS_FLAG2_RA 0x80 +#define DNS_FLAG2_ERR_MASK 0x0f +#define DNS_FLAG2_ERR_NONE 0x00 +#define DNS_FLAG2_ERR_NAME 0x03 + +#define SEND_BUFFER_SIZE 64 +#define RECV_BUFFER_SIZE 64 + +#ifdef CONFIG_NET_IPv6 +#define ADDRLEN sizeof(struct sockaddr_in6) +#else +#define ADDRLEN sizeof(struct sockaddr_in) +#endif + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/* The DNS message header */ + +struct dns_hdr +{ + uint16_t id; + uint8_t flags1, flags2; + uint16_t numquestions; + uint16_t numanswers; + uint16_t numauthrr; + uint16_t numextrarr; +}; + +/* The DNS answer message structure */ + +struct dns_answer +{ + /* DNS answer record starts with either a domain name or a pointer + * to a name already present somewhere in the packet. + */ + + uint16_t type; + uint16_t class; + uint16_t ttl[2]; + uint16_t len; +#ifdef CONFIG_NET_IPv6 + struct in6_addr ipaddr; +#else + struct in_addr ipaddr; +#endif +}; + +struct namemap +{ + uint8_t state; + uint8_t tmr; + uint8_t retries; + uint8_t seqno; + uint8_t err; + char name[32]; +#ifdef CONFIG_NET_IPv6 + struct in6_addr ipaddr; +#else + struct in_addr ipaddr; +#endif +}; + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +static uint8_t g_seqno; +static int g_sockfd = -1; +#ifdef CONFIG_NET_IPv6 +static struct sockaddr_in6 g_dnsserver; +#else +static struct sockaddr_in g_dnsserver; +#endif + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/* Walk through a compact encoded DNS name and return the end of it. */ + +static unsigned char *parse_name(unsigned char *query) +{ + unsigned char n; + + do + { + n = *query++; + + while(n > 0) + { + ++query; + --n; + } + } + while(*query != 0); + return query + 1; +} + +/* Runs through the list of names to see if there are any that have + * not yet been queried and, if so, sends out a query. + */ + +#ifdef CONFIG_NET_IPv6 +static int send_query(const char *name, struct sockaddr_in6 *addr) +#else +static int send_query(const char *name, struct sockaddr_in *addr) +#endif +{ + register struct dns_hdr *hdr; + char *query; + char *nptr; + const char *nameptr; + uint8_t seqno = g_seqno++; + static unsigned char endquery[] = {0, 0, 1, 0, 1}; + char buffer[SEND_BUFFER_SIZE]; + int n; + + hdr = (struct dns_hdr*)buffer; + memset(hdr, 0, sizeof(struct dns_hdr)); + hdr->id = htons(seqno); + hdr->flags1 = DNS_FLAG1_RD; + hdr->numquestions = HTONS(1); + query = buffer + 12; + + /* Convert hostname into suitable query format. */ + + nameptr = name - 1; + do + { + nameptr++; + nptr = query++; + for (n = 0; *nameptr != '.' && *nameptr != 0; nameptr++) + { + *query++ = *nameptr; + n++; + } + *nptr = n; + } + while(*nameptr != 0); + + memcpy(query, endquery, 5); + return sendto(g_sockfd, buffer, query + 5 - buffer, 0, (struct sockaddr*)addr, ADDRLEN); +} + +/* Called when new UDP data arrives */ + +#ifdef CONFIG_NET_IPv6 +#error "Not implemented" +#else +int recv_response(struct sockaddr_in *addr) +#endif +{ + unsigned char *nameptr; + char buffer[RECV_BUFFER_SIZE]; + struct dns_answer *ans; + struct dns_hdr *hdr; + uint8_t nquestions; + uint8_t nanswers; + int ret; + + /* Receive the response */ + + ret = recv(g_sockfd, buffer, RECV_BUFFER_SIZE, 0); + if (ret < 0) + { + return ret; + } + + hdr = (struct dns_hdr *)buffer; + + dbg( "ID %d\n", htons(hdr->id)); + dbg( "Query %d\n", hdr->flags1 & DNS_FLAG1_RESPONSE); + dbg( "Error %d\n", hdr->flags2 & DNS_FLAG2_ERR_MASK); + dbg( "Num questions %d, answers %d, authrr %d, extrarr %d\n", + htons(hdr->numquestions), htons(hdr->numanswers), + htons(hdr->numauthrr), htons(hdr->numextrarr)); + + /* Check for error. If so, call callback to inform */ + + if ((hdr->flags2 & DNS_FLAG2_ERR_MASK) != 0) + { + return ERROR; + } + + /* We only care about the question(s) and the answers. The authrr + * and the extrarr are simply discarded. + */ + + nquestions = htons(hdr->numquestions); + nanswers = htons(hdr->numanswers); + + /* Skip the name in the question. XXX: This should really be + * checked agains the name in the question, to be sure that they + * match. + */ + + nameptr = parse_name((unsigned char *)buffer + 12) + 4; + + for (; nanswers > 0; nanswers--) + { + /* The first byte in the answer resource record determines if it + * is a compressed record or a normal one. + */ + + if (*nameptr & 0xc0) + { + /* Compressed name. */ + + nameptr +=2; + dbg("Compressed anwser\n"); + } + else + { + /* Not compressed name. */ + nameptr = parse_name(nameptr); + } + + ans = (struct dns_answer *)nameptr; + dbg("Answer: type %x, class %x, ttl %x, length %x\n", + htons(ans->type), htons(ans->class), (htons(ans->ttl[0]) << 16) | htons(ans->ttl[1]), + htons(ans->len)); + + /* Check for IP address type and Internet class. Others are discarded. */ + + if (ans->type == HTONS(1) && ans->class == HTONS(1) && ans->len == HTONS(4)) + { + dbg("IP address %d.%d.%d.%d\n", + (ans->ipaddr.s_addr >> 24 ) & 0xff, + (ans->ipaddr.s_addr >> 16 ) & 0xff, + (ans->ipaddr.s_addr >> 8 ) & 0xff, + (ans->ipaddr.s_addr ) & 0xff); + + /* XXX: we should really check that this IP address is the one + * we want. + */ + + addr->sin_addr.s_addr = ans->ipaddr.s_addr; + return OK; + } + else + { + nameptr = nameptr + 10 + htons(ans->len); + } + } + return ERROR; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/* Get the binding for name. */ + +#ifdef CONFIG_NET_IPv6 +int resolv_query(FAR const char *name, FAR struct sockaddr_in6 *addr) +#else +int resolv_query(FAR const char *name, FAR struct sockaddr_in *addr) +#endif +{ + int retries; + int ret; + + /* Loop while receive timeout errors occur and there are remaining retries */ + + for (retries = 0; retries < 3; retries++) + { + if (send_query(name, addr) < 0) + { + return ERROR; + } + + ret = recv_response(addr); + if (ret >= 0) + { + /* Response received successfully */ + + return OK; + } + + else if (errno != EAGAIN) + { + /* Some failure other than receive timeout occurred */ + + return ERROR; + } + } + + return ERROR; +} + +/* Obtain the currently configured DNS server. */ + +#ifdef CONFIG_NET_IPv6 +void resolv_getserver(struct in6_addr *dnsserver) +#else +void resolv_getserver(struct in_addr *dnsserver) +#endif +{ +#ifdef CONFIG_NET_IPv6 + memcpy(dnsserver, &g_dnsserver.sin6_addr, ADDRLEN); +#else + dnsserver->s_addr = g_dnsserver.sin_addr.s_addr; +#endif +} + +/* Configure which DNS server to use for queries */ + +#ifdef CONFIG_NET_IPv6 +void resolv_conf(const struct in6_addr *dnsserver) +#else +void resolv_conf(const struct in_addr *dnsserver) +#endif +{ + g_dnsserver.sin_family = AF_INET; + g_dnsserver.sin_port = HTONS(53); +#ifdef CONFIG_NET_IPv6 + memcpy(&g_dnsserver.sin6_addr, dnsserver, ADDRLEN); +#else + g_dnsserver.sin_addr.s_addr = dnsserver->s_addr; +#endif +} + +/* Initalize the resolver. */ + +int resolv_init(void) +{ + struct timeval tv; + g_sockfd = socket(PF_INET, SOCK_DGRAM, 0); + if (g_sockfd < 0) + { + return ERROR; + } + + /* Set up a receive timeout */ + + tv.tv_sec = 30; + tv.tv_usec = 0; + if (setsockopt(g_sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval)) < 0) + { + close(g_sockfd); + g_sockfd = -1; + return ERROR; + } + + return OK; +} |