// SPDX-License-Identifier: GPL-2.0+
/*
 * efi_selftest_snp
 *
 * Copyright (c) 2017 Heinrich Schuchardt <xypron.glpk@gmx.de>
 *
 * This unit test covers the Simple Network Protocol as well as
 * the CopyMem and SetMem boottime services.
 *
 * A DHCP discover message is sent. The test is successful if a
 * DHCP reply is received.
 *
 * TODO: Once ConnectController and DisconnectController are implemented
 *       we should connect our code as controller.
 */

#include <efi_selftest.h>

/*
 * MAC address for broadcasts
 */
static const u8 BROADCAST_MAC[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

struct dhcp_hdr {
        u8 op;
#define BOOTREQUEST 1
#define BOOTREPLY 2
        u8 htype;
# define HWT_ETHER 1
        u8 hlen;
# define HWL_ETHER 6
        u8 hops;
        u32 xid;
        u16 secs;
        u16 flags;
#define DHCP_FLAGS_UNICAST      0x0000
#define DHCP_FLAGS_BROADCAST    0x0080
        u32 ciaddr;
        u32 yiaddr;
        u32 siaddr;
        u32 giaddr;
        u8 chaddr[16];
        u8 sname[64];
        u8 file[128];
};

/*
 * Message type option.
 */
#define DHCP_MESSAGE_TYPE       0x35
#define DHCPDISCOVER            1
#define DHCPOFFER               2
#define DHCPREQUEST             3
#define DHCPDECLINE             4
#define DHCPACK                 5
#define DHCPNAK                 6
#define DHCPRELEASE             7

struct dhcp {
        struct ethernet_hdr eth_hdr;
        struct ip_udp_hdr ip_udp;
        struct dhcp_hdr dhcp_hdr;
        u8 opt[128];
} __packed;

static struct efi_boot_services *boottime;
static struct efi_simple_network *net;
static struct efi_event *timer;
static const efi_guid_t efi_net_guid = EFI_SIMPLE_NETWORK_GUID;
/* IP packet ID */
static unsigned int net_ip_id;

/*
 * Compute the checksum of the IP header. We cover even values of length only.
 * We cannot use net/checksum.c due to different CFLAGS values.
 *
 * @buf:        IP header
 * @len:        length of header in bytes
 * @return:     checksum
 */
static unsigned int efi_ip_checksum(const void *buf, size_t len)
{
        size_t i;
        u32 sum = 0;
        const u16 *pos = buf;

        for (i = 0; i < len; i += 2)
                sum += *pos++;

        sum = (sum >> 16) + (sum & 0xffff);
        sum += sum >> 16;
        sum = ~sum & 0xffff;

        return sum;
}

/*
 * Transmit a DHCPDISCOVER message.
 */
static efi_status_t send_dhcp_discover(void)
{
        efi_status_t ret;
        struct dhcp p = {};

        /*
         * Fill ethernet header
         */
        boottime->copy_mem(p.eth_hdr.et_dest, (void *)BROADCAST_MAC, ARP_HLEN);
        boottime->copy_mem(p.eth_hdr.et_src, &net->mode->current_address,
                           ARP_HLEN);
        p.eth_hdr.et_protlen = htons(PROT_IP);
        /*
         * Fill IP header
         */
        p.ip_udp.ip_hl_v        = 0x45;
        p.ip_udp.ip_len         = htons(sizeof(struct dhcp) -
                                        sizeof(struct ethernet_hdr));
        p.ip_udp.ip_id          = htons(++net_ip_id);
        p.ip_udp.ip_off         = htons(IP_FLAGS_DFRAG);
        p.ip_udp.ip_ttl         = 0xff; /* time to live */
        p.ip_udp.ip_p           = IPPROTO_UDP;
        boottime->set_mem(&p.ip_udp.ip_dst, 4, 0xff);
        p.ip_udp.ip_sum         = efi_ip_checksum(&p.ip_udp, IP_HDR_SIZE);

        /*
         * Fill UDP header
         */
        p.ip_udp.udp_src        = htons(68);
        p.ip_udp.udp_dst        = htons(67);
        p.ip_udp.udp_len        = htons(sizeof(struct dhcp) -
                                        sizeof(struct ethernet_hdr) -
                                        sizeof(struct ip_hdr));
        /*
         * Fill DHCP header
         */
        p.dhcp_hdr.op           = BOOTREQUEST;
        p.dhcp_hdr.htype        = HWT_ETHER;
        p.dhcp_hdr.hlen         = HWL_ETHER;
        p.dhcp_hdr.flags        = htons(DHCP_FLAGS_UNICAST);
        boottime->copy_mem(&p.dhcp_hdr.chaddr,
                           &net->mode->current_address, ARP_HLEN);
        /*
         * Fill options
         */
        p.opt[0]        = 0x63; /* DHCP magic cookie */
        p.opt[1]        = 0x82;
        p.opt[2]        = 0x53;
        p.opt[3]        = 0x63;
        p.opt[4]        = DHCP_MESSAGE_TYPE;
        p.opt[5]        = 0x01; /* length */
        p.opt[6]        = DHCPDISCOVER;
        p.opt[7]        = 0x39; /* maximum message size */
        p.opt[8]        = 0x02; /* length */
        p.opt[9]        = 0x02; /* 576 bytes */
        p.opt[10]       = 0x40;
        p.opt[11]       = 0xff; /* end of options */

        /*
         * Transmit DHCPDISCOVER message.
         */
        ret = net->transmit(net, 0, sizeof(struct dhcp), &p, NULL, NULL, 0);
        if (ret != EFI_SUCCESS)
                efi_st_error("Sending a DHCP request failed\n");
        else
                efi_st_printf("DHCP Discover\n");
        return ret;
}

/*
 * Setup unit test.
 *
 * Create a 1 s periodic timer.
 * Start the network driver.
 *
 * @handle:     handle of the loaded image
 * @systable:   system table
 * @return:     EFI_ST_SUCCESS for success
 */
static int setup(const efi_handle_t handle,
                 const struct efi_system_table *systable)
{
        efi_status_t ret;

        boottime = systable->boottime;

        /*
         * Create a timer event.
         */
        ret = boottime->create_event(EVT_TIMER, TPL_CALLBACK, NULL, NULL,
                                     &timer);
        if (ret != EFI_SUCCESS) {
                efi_st_error("Failed to create event\n");
                return EFI_ST_FAILURE;
        }
        /*
         * Set timer period to 1s.
         */
        ret = boottime->set_timer(timer, EFI_TIMER_PERIODIC, 10000000);
        if (ret != EFI_SUCCESS) {
                efi_st_error("Failed to set timer\n");
                return EFI_ST_FAILURE;
        }
        /*
         * Find an interface implementing the SNP protocol.
         */
        ret = boottime->locate_protocol(&efi_net_guid, NULL, (void **)&net);
        if (ret != EFI_SUCCESS) {
                net = NULL;
                efi_st_error("Failed to locate simple network protocol\n");
                return EFI_ST_FAILURE;
        }
        /*
         * Check hardware address size.
         */
        if (!net->mode) {
                efi_st_error("Mode not provided\n");
                return EFI_ST_FAILURE;
        }
        if (net->mode->hwaddr_size != ARP_HLEN) {
                efi_st_error("HwAddressSize = %u, expected %u\n",
                             net->mode->hwaddr_size, ARP_HLEN);
                return EFI_ST_FAILURE;
        }
        /*
         * Check that WaitForPacket event exists.
         */
        if (!net->wait_for_packet) {
                efi_st_error("WaitForPacket event missing\n");
                return EFI_ST_FAILURE;
        }
        /*
         * Initialize network adapter.
         */
        ret = net->initialize(net, 0, 0);
        if (ret != EFI_SUCCESS) {
                efi_st_error("Failed to initialize network adapter\n");
                return EFI_ST_FAILURE;
        }
        /*
         * Start network adapter.
         */
        ret = net->start(net);
        if (ret != EFI_SUCCESS) {
                efi_st_error("Failed to start network adapter\n");
                return EFI_ST_FAILURE;
        }
        return EFI_ST_SUCCESS;
}

/*
 * Execute unit test.
 *
 * A DHCP discover message is sent. The test is successful if a
 * DHCP reply is received within 10 seconds.
 *
 * @return:     EFI_ST_SUCCESS for success
 */
static int execute(void)
{
        efi_status_t ret;
        struct efi_event *events[2];
        efi_uintn_t index;
        union {
                struct dhcp p;
                u8 b[PKTSIZE];
        } buffer;
        struct efi_mac_address srcaddr;
        struct efi_mac_address destaddr;
        size_t buffer_size;
        u8 *addr;
        /*
         * The timeout is to occur after 10 s.
         */
        unsigned int timeout = 10;

        /* Setup may have failed */
        if (!net || !timer) {
                efi_st_error("Cannot execute test after setup failure\n");
                return EFI_ST_FAILURE;
        }

        /*
         * Send DHCP discover message
         */
        ret = send_dhcp_discover();
        if (ret != EFI_SUCCESS)
                return EFI_ST_FAILURE;

        /*
         * If we would call WaitForEvent only with the WaitForPacket event,
         * our code would block until a packet is received which might never
         * occur. By calling WaitFor event with both a timer event and the
         * WaitForPacket event we can escape this blocking situation.
         *
         * If the timer event occurs before we have received a DHCP reply
         * a further DHCP discover message is sent.
         */
        events[0] = timer;
        events[1] = net->wait_for_packet;
        for (;;) {
                /*
                 * Wait for packet to be received or timer event.
                 */
                boottime->wait_for_event(2, events, &index);
                if (index == 0) {
                        /*
                         * The timer event occurred. Check for timeout.
                         */
                        --timeout;
                        if (!timeout) {
                                efi_st_error("Timeout occurred\n");
                                return EFI_ST_FAILURE;
                        }
                        /*
                         * Send further DHCP discover message
                         */
                        ret = send_dhcp_discover();
                        if (ret != EFI_SUCCESS)
                                return EFI_ST_FAILURE;
                        continue;
                }
                /*
                 * Receive packet
                 */
                buffer_size = sizeof(buffer);
                net->receive(net, NULL, &buffer_size, &buffer,
                             &srcaddr, &destaddr, NULL);
                if (ret != EFI_SUCCESS) {
                        efi_st_error("Failed to receive packet");
                        return EFI_ST_FAILURE;
                }
                /*
                 * Check the packet is meant for this system.
                 * Unfortunately QEMU ignores the broadcast flag.
                 * So we have to check for broadcasts too.
                 */
                if (efi_st_memcmp(&destaddr, &net->mode->current_address,
                                  ARP_HLEN) &&
                    efi_st_memcmp(&destaddr, BROADCAST_MAC, ARP_HLEN))
                        continue;
                /*
                 * Check this is a DHCP reply
                 */
                if (buffer.p.eth_hdr.et_protlen != ntohs(PROT_IP) ||
                    buffer.p.ip_udp.ip_hl_v != 0x45 ||
                    buffer.p.ip_udp.ip_p != IPPROTO_UDP ||
                    buffer.p.ip_udp.udp_src != ntohs(67) ||
                    buffer.p.ip_udp.udp_dst != ntohs(68) ||
                    buffer.p.dhcp_hdr.op != BOOTREPLY)
                        continue;
                /*
                 * We successfully received a DHCP reply.
                 */
                break;
        }

        /*
         * Write a log message.
         */
        addr = (u8 *)&buffer.p.ip_udp.ip_src;
        efi_st_printf("DHCP reply received from %u.%u.%u.%u (%pm) ",
                      addr[0], addr[1], addr[2], addr[3], &srcaddr);
        if (!efi_st_memcmp(&destaddr, BROADCAST_MAC, ARP_HLEN))
                efi_st_printf("as broadcast message.\n");
        else
                efi_st_printf("as unicast message.\n");

        return EFI_ST_SUCCESS;
}

/*
 * Tear down unit test.
 *
 * Close the timer event created in setup.
 * Shut down the network adapter.
 *
 * @return:     EFI_ST_SUCCESS for success
 */
static int teardown(void)
{
        efi_status_t ret;
        int exit_status = EFI_ST_SUCCESS;

        if (timer) {
                /*
                 * Stop timer.
                 */
                ret = boottime->set_timer(timer, EFI_TIMER_STOP, 0);
                if (ret != EFI_SUCCESS) {
                        efi_st_error("Failed to stop timer");
                        exit_status = EFI_ST_FAILURE;
                }
                /*
                 * Close timer event.
                 */
                ret = boottime->close_event(timer);
                if (ret != EFI_SUCCESS) {
                        efi_st_error("Failed to close event");
                        exit_status = EFI_ST_FAILURE;
                }
        }
        if (net) {
                /*
                 * Stop network adapter.
                 */
                ret = net->stop(net);
                if (ret != EFI_SUCCESS) {
                        efi_st_error("Failed to stop network adapter\n");
                        exit_status = EFI_ST_FAILURE;
                }
                /*
                 * Shut down network adapter.
                 */
                ret = net->shutdown(net);
                if (ret != EFI_SUCCESS) {
                        efi_st_error("Failed to shut down network adapter\n");
                        exit_status = EFI_ST_FAILURE;
                }
        }

        return exit_status;
}

EFI_UNIT_TEST(snp) = {
        .name = "simple network protocol",
        .phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
        .setup = setup,
        .execute = execute,
        .teardown = teardown,
};