151 lines
4.0 KiB
C
151 lines
4.0 KiB
C
/**
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******************************************************************************
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* @file dns_eloop.c
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* @author HUGE-IC Application Team
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* @version V1.0.0
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* @date 2021-07-16
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* @brief a simple dns server
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******************************************************************************
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* @attention
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*
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* <h2><center>© COPYRIGHT 2021 HUGE-IC</center></h2>
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*
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*
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******************************************************************************
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*/
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#include "typesdef.h"
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#include "list.h"
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#include "osal/task.h"
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#include "osal/string.h"
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#include "osal/sleep.h"
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#include "lib/common/sysevt.h"
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#include "lwip/opt.h"
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#include "lwip/sockets.h"
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#include "netif/ethernetif.h"
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#include "lwip/ip.h"
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#include "lwip/init.h"
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#include "lwip/prot/dns.h"
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//#include "lib/net/dns/dns.h"
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#include "dns_eloop.h"
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#include "event.h"
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#define dns_dbg(fmt, ...) os_printf(fmt, ##__VA_ARGS__)
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#define dns_err(fmt, ...) os_printf(fmt, ##__VA_ARGS__)
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#define DNS_RECVBUF_SIZE (512)
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struct dns_mgr {
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struct netif *netif;
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int32 sock;
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uint8 recvbuf[DNS_RECVBUF_SIZE];
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uint8 stop: 1;
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};
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static struct dns_mgr *dns;
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static void dns_query_refuse(struct sockaddr_in *addr, uint8 *data, uint32 len)
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{
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struct dns_hdr *hdr = (struct dns_hdr *)data;
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// 置起flags中response，并且返回query失败原因, 我们并未实现dns功能，只是拒绝了查询
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hdr->flags1 |= DNS_FLAG1_RESPONSE;
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hdr->flags2 &= ~DNS_FLAG2_ERR_MASK;
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hdr->flags2 |= 5; // 5: Refused - 服务器拒绝执行请求操作
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sendto(dns->sock, data, len, 0, (const struct sockaddr *)addr, sizeof(struct sockaddr));
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//dns_dbg("dns query refused - %s:%d\r\n", inet_ntoa(addr->sin_addr), ntohs(addr->sin_port));
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}
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static void dns_task_eloop(void *ei, void *d)
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{
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int32 ret = 0;
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socklen_t len = 16; // 接收socket地址需要用
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struct sockaddr_in addr;
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struct dns_hdr *hdr;
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ret = recvfrom(dns->sock, dns->recvbuf, DNS_RECVBUF_SIZE, 0, (struct sockaddr *)&addr, &len);
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// 最少dns_hdr长度12
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if (ret >= 12 && !dns->stop) {
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hdr = (struct dns_hdr *)dns->recvbuf;
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// 最少dns_hdr + dns_query = 12 + 4
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if (hdr->numquestions > 0 && ret >= (12 + 4)) {
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dns_query_refuse(&addr, dns->recvbuf, ret);
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}
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}
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}
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__init static int32 _dns_start(char *ifname)
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{
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int32 ret = -1;
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int32 sock = -1;
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int32 optval = 1;
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struct sockaddr_in local_addr;
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struct ifreq nif;
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dns = os_zalloc(sizeof(struct dns_mgr));
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if(dns == NULL)
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return -ENOMEM;
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dns->netif = netif_find(ifname);
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if (dns->netif == NULL) {
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dns_err("netif:%s is not exist\r\n", ifname);
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return RET_ERR;
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}
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sock = socket(AF_INET, SOCK_DGRAM, 0);
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if (sock == -1) {
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dns_err("create socket failed\r\n");
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return RET_ERR;
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}
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fcntl(sock, F_SETFL, O_NONBLOCK);
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setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval));
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os_strncpy(nif.ifr_name, dns->netif->name, 2);
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setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, &nif, sizeof(nif));
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os_memset(&local_addr, 0, sizeof(local_addr));
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local_addr.sin_family = AF_INET;
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local_addr.sin_port = htons(53);
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local_addr.sin_addr.s_addr = dns->netif->ip_addr.addr;
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ret = bind(sock, (struct sockaddr *)&local_addr, sizeof(struct sockaddr));
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if (ret == -1) {
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dns_err("bind fail\r\n");
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closesocket(sock);
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return RET_ERR;
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}
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dns->sock = sock;
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dns_dbg("dns sock :%x\r\n", (uint32)sock);
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eloop_add_fd(dns->sock, EVENT_READ, EVENT_F_ENABLED, dns_task_eloop, NULL);
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return RET_OK;
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}
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int32 dns_start_eloop(char *ifname)
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{
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int32 ret = 0;
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if (ifname == NULL) {
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dns_err("invalid param!\r\n");
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return RET_ERR;
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}
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if (dns) {
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dns->stop = 0;
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dns_err("dns already running ...\r\n");
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return RET_OK;
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}
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ret = _dns_start(ifname);
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ASSERT(!ret);
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return ret;
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}
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void dns_stop_eloop(char *ifname)
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{
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if(dns){
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dns->stop = 1;
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}
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}
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