dhcpserver/dhcpserver.c (access_point sample)

Outline

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include "cyw43_config.h"

#include "dhcpserver.h"

#include "lwip/udp.h"

#define DHCPDISCOVER

#define DHCPOFFER

#define DHCPREQUEST

#define DHCPDECLINE

#define DHCPACK

#define DHCPNACK

#define DHCPRELEASE

#define DHCPINFORM

#define DHCP_OPT_PAD

#define DHCP_OPT_SUBNET_MASK

#define DHCP_OPT_ROUTER

#define DHCP_OPT_DNS

#define DHCP_OPT_HOST_NAME

#define DHCP_OPT_REQUESTED_IP

#define DHCP_OPT_IP_LEASE_TIME

#define DHCP_OPT_MSG_TYPE

#define DHCP_OPT_SERVER_ID

#define DHCP_OPT_PARAM_REQUEST_LIST

#define DHCP_OPT_MAX_MSG_SIZE

#define DHCP_OPT_VENDOR_CLASS_ID

#define DHCP_OPT_CLIENT_ID

#define DHCP_OPT_END

#define PORT_DHCP_SERVER

#define PORT_DHCP_CLIENT

#define DEFAULT_LEASE_TIME_S

#define MAC_LEN

#define MAKE_IP4

dhcp_socket_new_dgram(struct udp_pcb **, void *, int)

dhcp_socket_free(struct udp_pcb **)

dhcp_socket_bind(struct udp_pcb **, int)

dhcp_socket_sendto(struct udp_pcb **, struct netif *, const void *, size_t, int, int)

opt_find(int *, int)

opt_write_n(int **, int, size_t, const void *)

opt_write_u8(int **, int, int)

opt_write_u32(int **, int, int)

dhcp_server_process(void *, struct udp_pcb *, struct pbuf *, const int *, int)

dhcp_server_init(dhcp_server_t *, int *, int *)

dhcp_server_deinit(dhcp_server_t *)

Files

SourceVuRaspberry Pi Pico SDK and Examplesaccess_point sampledhcpserver/dhcpserver.c

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/* * This file is part of the MicroPython project, http://micropython.org/ * * The MIT License (MIT) * * Copyright (c) 2018-2019 Damien P. George * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ // For DHCP specs see: // https://www.ietf.org/rfc/rfc2131.txt // https://tools.ietf.org/html/rfc2132 -- DHCP Options and BOOTP Vendor Extensions #include <stdio.h> #include <string.h> #include <errno.h> #include "cyw43_config.h" #include "dhcpserver.h" #include "lwip/udp.h" #define DHCPDISCOVER (1) #define DHCPOFFER (2) #define DHCPREQUEST (3) #define DHCPDECLINE (4) #define DHCPACK (5) #define DHCPNACK (6) #define DHCPRELEASE (7) #define DHCPINFORM (8) #define DHCP_OPT_PAD (0) #define DHCP_OPT_SUBNET_MASK (1) #define DHCP_OPT_ROUTER (3) #define DHCP_OPT_DNS (6) #define DHCP_OPT_HOST_NAME (12) #define DHCP_OPT_REQUESTED_IP (50) #define DHCP_OPT_IP_LEASE_TIME (51) #define DHCP_OPT_MSG_TYPE (53) #define DHCP_OPT_SERVER_ID (54) #define DHCP_OPT_PARAM_REQUEST_LIST (55) #define DHCP_OPT_MAX_MSG_SIZE (57) #define DHCP_OPT_VENDOR_CLASS_ID (60) #define DHCP_OPT_CLIENT_ID (61) #define DHCP_OPT_END (255) #define PORT_DHCP_SERVER (67) #define PORT_DHCP_CLIENT (68) #define DEFAULT_LEASE_TIME_S (24 * 60 * 60) // in seconds #define MAC_LEN (6) #define MAKE_IP4(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d)) typedef struct { uint8_t op; // message opcode uint8_t htype; // hardware address type uint8_t hlen; // hardware address length uint8_t hops; uint32_t xid; // transaction id, chosen by client uint16_t secs; // client seconds elapsed uint16_t flags; uint8_t ciaddr[4]; // client IP address uint8_t yiaddr[4]; // your IP address uint8_t siaddr[4]; // next server IP address uint8_t giaddr[4]; // relay agent IP address uint8_t chaddr[16]; // client hardware address uint8_t sname[64]; // server host name uint8_t file[128]; // boot file name uint8_t options[312]; // optional parameters, variable, starts with magic } dhcp_msg_t; static int dhcp_socket_new_dgram(struct udp_pcb **udp, void *cb_data, udp_recv_fn cb_udp_recv) { // family is AF_INET // type is SOCK_DGRAM *udp = udp_new(); if (*udp == NULL) { return -ENOMEM; } // Register callback udp_recv(*udp, cb_udp_recv, (void *)cb_data); return 0; // success } static void dhcp_socket_free(struct udp_pcb **udp) { if (*udp != NULL) { udp_remove(*udp); *udp = NULL; } } static int dhcp_socket_bind(struct udp_pcb **udp, uint16_t port) { // TODO convert lwIP errors to errno return udp_bind(*udp, IP_ANY_TYPE, port); } static int dhcp_socket_sendto(struct udp_pcb **udp, struct netif *nif, const void *buf, size_t len, uint32_t ip, uint16_t port) { if (len > 0xffff) { len = 0xffff; } struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, len, PBUF_RAM); if (p == NULL) { return -ENOMEM; } memcpy(p->payload, buf, len); ip_addr_t dest; IP4_ADDR(ip_2_ip4(&dest), ip >> 24 & 0xff, ip >> 16 & 0xff, ip >> 8 & 0xff, ip & 0xff); err_t err; if (nif != NULL) { err = udp_sendto_if(*udp, p, &dest, port, nif); } else { err = udp_sendto(*udp, p, &dest, port); } pbuf_free(p); if (err != ERR_OK) { return err; } return len; } static uint8_t *opt_find(uint8_t *opt, uint8_t cmd) { for (int i = 0; i < 308 && opt[i] != DHCP_OPT_END;) { if (opt[i] == cmd) { return &opt[i]; } i += 2 + opt[i + 1]; } return NULL; } static void opt_write_n(uint8_t **opt, uint8_t cmd, size_t n, const void *data) { uint8_t *o = *opt; *o++ = cmd; *o++ = n; memcpy(o, data, n); *opt = o + n; } static void opt_write_u8(uint8_t **opt, uint8_t cmd, uint8_t val) { uint8_t *o = *opt; *o++ = cmd; *o++ = 1; *o++ = val; *opt = o; } static void opt_write_u32(uint8_t **opt, uint8_t cmd, uint32_t val) { uint8_t *o = *opt; *o++ = cmd; *o++ = 4; *o++ = val >> 24; *o++ = val >> 16; *o++ = val >> 8; *o++ = val; *opt = o; } static void dhcp_server_process(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *src_addr, u16_t src_port) { dhcp_server_t *d = arg; (void)upcb; (void)src_addr; (void)src_port; // This is around 548 bytes dhcp_msg_t dhcp_msg; #define DHCP_MIN_SIZE (240 + 3) if (p->tot_len < DHCP_MIN_SIZE) { goto ignore_request; } size_t len = pbuf_copy_partial(p, &dhcp_msg, sizeof(dhcp_msg), 0); if (len < DHCP_MIN_SIZE) { goto ignore_request; } dhcp_msg.op = DHCPOFFER; memcpy(&dhcp_msg.yiaddr, &ip4_addr_get_u32(ip_2_ip4(&d->ip)), 4); uint8_t *opt = (uint8_t *)&dhcp_msg.options; opt += 4; // assume magic cookie: 99, 130, 83, 99 uint8_t *msgtype = opt_find(opt, DHCP_OPT_MSG_TYPE); if (msgtype == NULL) { // A DHCP package without MSG_TYPE? goto ignore_request; } switch (msgtype[2]) { case DHCPDISCOVER: { int yi = DHCPS_MAX_IP; for (int i = 0; i < DHCPS_MAX_IP; ++i) { if (memcmp(d->lease[i].mac, dhcp_msg.chaddr, MAC_LEN) == 0) { // MAC match, use this IP address yi = i; break; } if (yi == DHCPS_MAX_IP) { // Look for a free IP address if (memcmp(d->lease[i].mac, "\x00\x00\x00\x00\x00\x00", MAC_LEN) == 0) { // IP available yi = i; } uint32_t expiry = d->lease[i].expiry << 16 | 0xffff; if ((int32_t)(expiry - cyw43_hal_ticks_ms()) < 0) { // IP expired, reuse it memset(d->lease[i].mac, 0, MAC_LEN); yi = i; } } } if (yi == DHCPS_MAX_IP) { // No more IP addresses left goto ignore_request; } dhcp_msg.yiaddr[3] = DHCPS_BASE_IP + yi; opt_write_u8(&opt, DHCP_OPT_MSG_TYPE, DHCPOFFER); break; } case DHCPREQUEST: { uint8_t *o = opt_find(opt, DHCP_OPT_REQUESTED_IP); if (o == NULL) { // Should be NACK goto ignore_request; } if (memcmp(o + 2, &ip4_addr_get_u32(ip_2_ip4(&d->ip)), 3) != 0) { // Should be NACK goto ignore_request; } uint8_t yi = o[5] - DHCPS_BASE_IP; if (yi >= DHCPS_MAX_IP) { // Should be NACK goto ignore_request; } if (memcmp(d->lease[yi].mac, dhcp_msg.chaddr, MAC_LEN) == 0) { // MAC match, ok to use this IP address } else if (memcmp(d->lease[yi].mac, "\x00\x00\x00\x00\x00\x00", MAC_LEN) == 0) { // IP unused, ok to use this IP address memcpy(d->lease[yi].mac, dhcp_msg.chaddr, MAC_LEN); } else { // IP already in use // Should be NACK goto ignore_request; } d->lease[yi].expiry = (cyw43_hal_ticks_ms() + DEFAULT_LEASE_TIME_S * 1000) >> 16; dhcp_msg.yiaddr[3] = DHCPS_BASE_IP + yi; opt_write_u8(&opt, DHCP_OPT_MSG_TYPE, DHCPACK); printf("DHCPS: client connected: MAC=%02x:%02x:%02x:%02x:%02x:%02x IP=%u.%u.%u.%u\n", dhcp_msg.chaddr[0], dhcp_msg.chaddr[1], dhcp_msg.chaddr[2], dhcp_msg.chaddr[3], dhcp_msg.chaddr[4], dhcp_msg.chaddr[5], dhcp_msg.yiaddr[0], dhcp_msg.yiaddr[1], dhcp_msg.yiaddr[2], dhcp_msg.yiaddr[3]); break; } default: goto ignore_request; } opt_write_n(&opt, DHCP_OPT_SERVER_ID, 4, &ip4_addr_get_u32(ip_2_ip4(&d->ip))); opt_write_n(&opt, DHCP_OPT_SUBNET_MASK, 4, &ip4_addr_get_u32(ip_2_ip4(&d->nm))); opt_write_n(&opt, DHCP_OPT_ROUTER, 4, &ip4_addr_get_u32(ip_2_ip4(&d->ip))); // aka gateway; can have multiple addresses opt_write_n(&opt, DHCP_OPT_DNS, 4, &ip4_addr_get_u32(ip_2_ip4(&d->ip))); // this server is the dns opt_write_u32(&opt, DHCP_OPT_IP_LEASE_TIME, DEFAULT_LEASE_TIME_S); *opt++ = DHCP_OPT_END; struct netif *nif = ip_current_input_netif(); dhcp_socket_sendto(&d->udp, nif, &dhcp_msg, opt - (uint8_t *)&dhcp_msg, 0xffffffff, PORT_DHCP_CLIENT); ignore_request: pbuf_free(p); } void dhcp_server_init(dhcp_server_t *d, ip_addr_t *ip, ip_addr_t *nm) { ip_addr_copy(d->ip, *ip); ip_addr_copy(d->nm, *nm); memset(d->lease, 0, sizeof(d->lease)); if (dhcp_socket_new_dgram(&d->udp, d, dhcp_server_process) != 0) { return; } dhcp_socket_bind(&d->udp, PORT_DHCP_SERVER); } void dhcp_server_deinit(dhcp_server_t *d) { dhcp_socket_free(&d->udp); }

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