Archipelago » qemu

#include "slirp.h"

/* host address */

struct in_addr our_addr;

/* host dns address */

struct in_addr dns_addr;

/* host loopback address */

struct in_addr loopback_addr;

/* address for slirp virtual addresses */

struct in_addr special_addr;

const uint8_t special_ethaddr[6] = { 

    0x52, 0x54, 0x00, 0x12, 0x35, 0x00

};

uint8_t client_ethaddr[6];

int do_slowtimo;

int link_up;

struct timeval tt;

FILE *lfd;

/* XXX: suppress those select globals */

fd_set *global_readfds, *global_writefds, *global_xfds;

#ifdef _WIN32

static int get_dns_addr(struct in_addr *pdns_addr)

{

    /* XXX: add it */

    return -1;

}

#else

static int get_dns_addr(struct in_addr *pdns_addr)

{

    char buff[512];

    char buff2[256];

    FILE *f;

    int found = 0;

    struct in_addr tmp_addr;

    f = fopen("/etc/resolv.conf", "r");

    if (!f)

        return -1;

    lprint("IP address of your DNS(s): ");

    while (fgets(buff, 512, f) != NULL) {

        if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {

            if (!inet_aton(buff2, &tmp_addr))

                continue;

            if (tmp_addr.s_addr == loopback_addr.s_addr)

                tmp_addr = our_addr;

            /* If it's the first one, set it to dns_addr */

            if (!found)

                *pdns_addr = tmp_addr;

            else

                lprint(", ");

            if (++found > 3) {

                lprint("(more)");

                break;

            } else

                lprint("%s", inet_ntoa(tmp_addr));

        }

    }

    if (!found)

        return -1;

    return 0;

}

#endif

void slirp_init(void)

{

    //    debug_init("/tmp/slirp.log", DEBUG_DEFAULT);

    link_up = 1;

    if_init();

    ip_init();

    /* Initialise mbufs *after* setting the MTU */

    m_init();

    /* set default addresses */

    getouraddr();

    inet_aton("127.0.0.1", &loopback_addr);

    if (get_dns_addr(&dns_addr) < 0) {

        fprintf(stderr, "Could not get DNS address\n");

        exit(1);

    }

    inet_aton(CTL_SPECIAL, &special_addr);

}

#define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)

#define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)

#define UPD_NFDS(x) if (nfds < (x)) nfds = (x)

/*

 * curtime kept to an accuracy of 1ms

 */

static void updtime(void)

{

        gettimeofday(&tt, 0);

        curtime = (u_int)tt.tv_sec * (u_int)1000;

        curtime += (u_int)tt.tv_usec / (u_int)1000;

        if ((tt.tv_usec % 1000) >= 500)

           curtime++;

}

void slirp_select_fill(int *pnfds, 

                       fd_set *readfds, fd_set *writefds, fd_set *xfds)

{

    struct socket *so, *so_next;

    struct timeval timeout;

    int nfds;

    int tmp_time;

    /* fail safe */

    global_readfds = NULL;

    global_writefds = NULL;

    global_xfds = NULL;

    nfds = *pnfds;

        /*

         * First, TCP sockets

         */

        do_slowtimo = 0;

        if (link_up) {

                /* 

                 * *_slowtimo needs calling if there are IP fragments

                 * in the fragment queue, or there are TCP connections active

                 */

                do_slowtimo = ((tcb.so_next != &tcb) ||

                               ((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next));

                for (so = tcb.so_next; so != &tcb; so = so_next) {

                        so_next = so->so_next;

                        /*

                         * See if we need a tcp_fasttimo

                         */

                        if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK)

                           time_fasttimo = curtime; /* Flag when we want a fasttimo */

                        /*

                         * NOFDREF can include still connecting to local-host,

                         * newly socreated() sockets etc. Don't want to select these.

                          */

                        if (so->so_state & SS_NOFDREF || so->s == -1)

                           continue;

                        /*

                         * Set for reading sockets which are accepting

                         */

                        if (so->so_state & SS_FACCEPTCONN) {

                                FD_SET(so->s, readfds);

                                UPD_NFDS(so->s);

                                continue;

                        }

                        /*

                         * Set for writing sockets which are connecting

                         */

                        if (so->so_state & SS_ISFCONNECTING) {

                                FD_SET(so->s, writefds);

                                UPD_NFDS(so->s);

                                continue;

                        }

                        /*

                         * Set for writing if we are connected, can send more, and

                         * we have something to send

                         */

                        if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {

                                FD_SET(so->s, writefds);

                                UPD_NFDS(so->s);

                        }

                        /*

                         * Set for reading (and urgent data) if we are connected, can

                         * receive more, and we have room for it XXX /2 ?

                         */

                        if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {

                                FD_SET(so->s, readfds);

                                FD_SET(so->s, xfds);

                                UPD_NFDS(so->s);

                        }

                }

                /*

                 * UDP sockets

                 */

                for (so = udb.so_next; so != &udb; so = so_next) {

                        so_next = so->so_next;

                        /*

                         * See if it's timed out

                         */

                        if (so->so_expire) {

                                if (so->so_expire <= curtime) {

                                        udp_detach(so);

                                        continue;

                                } else

                                        do_slowtimo = 1; /* Let socket expire */

                        }

                        /*

                         * When UDP packets are received from over the

                         * link, they're sendto()'d straight away, so

                         * no need for setting for writing

                         * Limit the number of packets queued by this session

                         * to 4.  Note that even though we try and limit this

                         * to 4 packets, the session could have more queued

                         * if the packets needed to be fragmented

                         * (XXX <= 4 ?)

                         */

                        if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {

                                FD_SET(so->s, readfds);

                                UPD_NFDS(so->s);

                        }

                }

        }

        /*

         * Setup timeout to use minimum CPU usage, especially when idle

         */

        /* 

         * First, see the timeout needed by *timo

         */

        timeout.tv_sec = 0;

        timeout.tv_usec = -1;

        /*

         * If a slowtimo is needed, set timeout to 500ms from the last

         * slow timeout. If a fast timeout is needed, set timeout within

         * 200ms of when it was requested.

         */

        if (do_slowtimo) {

                /* XXX + 10000 because some select()'s aren't that accurate */

                timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000;

                if (timeout.tv_usec < 0)

                   timeout.tv_usec = 0;

                else if (timeout.tv_usec > 510000)

                   timeout.tv_usec = 510000;

                /* Can only fasttimo if we also slowtimo */

                if (time_fasttimo) {

                        tmp_time = (200 - (curtime - time_fasttimo)) * 1000;

                        if (tmp_time < 0)

                           tmp_time = 0;

                        /* Choose the smallest of the 2 */

                        if (tmp_time < timeout.tv_usec)

                           timeout.tv_usec = (u_int)tmp_time;

                }

        }

        *pnfds = nfds;

}        

void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)

{

    struct socket *so, *so_next;

    int ret;

    global_readfds = readfds;

    global_writefds = writefds;

    global_xfds = xfds;

        /* Update time */

        updtime();

        /*

         * See if anything has timed out 

         */

        if (link_up) {

                if (time_fasttimo && ((curtime - time_fasttimo) >= 199)) {

                        tcp_fasttimo();

                        time_fasttimo = 0;

                }

                if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {

                        ip_slowtimo();

                        tcp_slowtimo();

                        last_slowtimo = curtime;

                }

        }

        /*

         * Check sockets

         */

        if (link_up) {

                /*

                 * Check TCP sockets

                 */

                for (so = tcb.so_next; so != &tcb; so = so_next) {

                        so_next = so->so_next;

                        /*

                         * FD_ISSET is meaningless on these sockets

                         * (and they can crash the program)

                         */

                        if (so->so_state & SS_NOFDREF || so->s == -1)

                           continue;

                        /*

                         * Check for URG data

                         * This will soread as well, so no need to

                         * test for readfds below if this succeeds

                         */

                        if (FD_ISSET(so->s, xfds))

                           sorecvoob(so);

                        /*

                         * Check sockets for reading

                         */

                        else if (FD_ISSET(so->s, readfds)) {

                                /*

                                 * Check for incoming connections

                                 */

                                if (so->so_state & SS_FACCEPTCONN) {

                                        tcp_connect(so);

                                        continue;

                                } /* else */

                                ret = soread(so);

                                /* Output it if we read something */

                                if (ret > 0)

                                   tcp_output(sototcpcb(so));

                        }

                        /*

                         * Check sockets for writing

                         */

                        if (FD_ISSET(so->s, writefds)) {

                          /*

                           * Check for non-blocking, still-connecting sockets

                           */

                          if (so->so_state & SS_ISFCONNECTING) {

                            /* Connected */

                            so->so_state &= ~SS_ISFCONNECTING;

                            ret = write(so->s, &ret, 0);

                            if (ret < 0) {

                              /* XXXXX Must fix, zero bytes is a NOP */

                              if (errno == EAGAIN || errno == EWOULDBLOCK ||

                                  errno == EINPROGRESS || errno == ENOTCONN)

                                continue;

                              /* else failed */

                              so->so_state = SS_NOFDREF;

                            }

                            /* else so->so_state &= ~SS_ISFCONNECTING; */

                            /*

                             * Continue tcp_input

                             */

                            tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);

                            /* continue; */

                          } else

                            ret = sowrite(so);

                          /*

                           * XXXXX If we wrote something (a lot), there 

                           * could be a need for a window update.

                           * In the worst case, the remote will send

                           * a window probe to get things going again

                           */

                        }

                        /*

                         * Probe a still-connecting, non-blocking socket

                         * to check if it's still alive

                           */

#ifdef PROBE_CONN

                        if (so->so_state & SS_ISFCONNECTING) {

                          ret = read(so->s, (char *)&ret, 0);

                          if (ret < 0) {

                            /* XXX */

                            if (errno == EAGAIN || errno == EWOULDBLOCK ||

                                errno == EINPROGRESS || errno == ENOTCONN)

                              continue; /* Still connecting, continue */

                            /* else failed */

                            so->so_state = SS_NOFDREF;

                            /* tcp_input will take care of it */

                          } else {

                            ret = write(so->s, &ret, 0);

                            if (ret < 0) {

                              /* XXX */

                              if (errno == EAGAIN || errno == EWOULDBLOCK ||

                                  errno == EINPROGRESS || errno == ENOTCONN)

                                continue;

                              /* else failed */

                              so->so_state = SS_NOFDREF;

                            } else

                              so->so_state &= ~SS_ISFCONNECTING;

                          }

                          tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);

                        } /* SS_ISFCONNECTING */

#endif

                }

                /*

                 * Now UDP sockets.

                 * Incoming packets are sent straight away, they're not buffered.

                 * Incoming UDP data isn't buffered either.

                 */

                for (so = udb.so_next; so != &udb; so = so_next) {

                        so_next = so->so_next;

                        if (so->s != -1 && FD_ISSET(so->s, readfds)) {

                            sorecvfrom(so);

                        }

                }

        }

        /*

         * See if we can start outputting

         */

        if (if_queued && link_up)

           if_start();

}

#define ETH_ALEN 6

#define ETH_HLEN 14

#define ETH_P_IP        0x0800                /* Internet Protocol packet        */

#define ETH_P_ARP        0x0806                /* Address Resolution packet        */

#define        ARPOP_REQUEST        1                /* ARP request                        */

#define        ARPOP_REPLY        2                /* ARP reply                        */

struct ethhdr 

{

        unsigned char        h_dest[ETH_ALEN];        /* destination eth addr        */

        unsigned char        h_source[ETH_ALEN];        /* source ether addr        */

        unsigned short        h_proto;                /* packet type ID field        */

};

struct arphdr

{

        unsigned short        ar_hrd;                /* format of hardware address        */

        unsigned short        ar_pro;                /* format of protocol address        */

        unsigned char        ar_hln;                /* length of hardware address        */

        unsigned char        ar_pln;                /* length of protocol address        */

        unsigned short        ar_op;                /* ARP opcode (command)                */

         /*

          *         Ethernet looks like this : This bit is variable sized however...

          */

        unsigned char                ar_sha[ETH_ALEN];        /* sender hardware address        */

        unsigned char                ar_sip[4];                /* sender IP address                */

        unsigned char                ar_tha[ETH_ALEN];        /* target hardware address        */

        unsigned char                ar_tip[4];                /* target IP address                */

};

void arp_input(const uint8_t *pkt, int pkt_len)

{

    struct ethhdr *eh = (struct ethhdr *)pkt;

    struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);

    uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)];

    struct ethhdr *reh = (struct ethhdr *)arp_reply;

    struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);

    int ar_op;

    ar_op = ntohs(ah->ar_op);

    switch(ar_op) {

    case ARPOP_REQUEST:

        if (!memcmp(ah->ar_tip, &special_addr, 3) &&

            (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS)) {

            /* XXX: make an ARP request to have the client address */

            memcpy(client_ethaddr, eh->h_source, ETH_ALEN);

            /* ARP request for alias/dns mac address */

            memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);

            memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1);

            reh->h_source[5] = ah->ar_tip[3];

            reh->h_proto = htons(ETH_P_ARP);

            rah->ar_hrd = htons(1);

            rah->ar_pro = htons(ETH_P_IP);

            rah->ar_hln = ETH_ALEN;

            rah->ar_pln = 4;

            rah->ar_op = htons(ARPOP_REPLY);

            memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);

            memcpy(rah->ar_sip, ah->ar_tip, 4);

            memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);

            memcpy(rah->ar_tip, ah->ar_sip, 4);

            slirp_output(arp_reply, sizeof(arp_reply));

        }

        break;

    default:

        break;

    }

}

void slirp_input(const uint8_t *pkt, int pkt_len)

{

    struct mbuf *m;

    int proto;

    if (pkt_len < ETH_HLEN)

        return;

    proto = ntohs(*(uint16_t *)(pkt + 12));

    switch(proto) {

    case ETH_P_ARP:

        arp_input(pkt, pkt_len);

        break;

    case ETH_P_IP:

        m = m_get();

        if (!m)

            return;

        m->m_len = pkt_len;

        memcpy(m->m_data, pkt, pkt_len);

        m->m_data += ETH_HLEN;

        m->m_len -= ETH_HLEN;

        ip_input(m);

        break;

    default:

        break;

    }

}

/* output the IP packet to the ethernet device */

void if_encap(const uint8_t *ip_data, int ip_data_len)

{

    uint8_t buf[1600];

    struct ethhdr *eh = (struct ethhdr *)buf;

    if (ip_data_len + ETH_HLEN > sizeof(buf))

        return;

    memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);

    memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);

    eh->h_source[5] = CTL_ALIAS;

    eh->h_proto = htons(ETH_P_IP);

    memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);

    slirp_output(buf, ip_data_len + ETH_HLEN);

}