source: trunk/minix/lib/ip/recvfrom.c@ 21

#undef NDEBUG

#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <net/gen/in.h>
#include <net/gen/udp.h>
#include <net/gen/udp_hdr.h>
#include <net/gen/udp_io.h>

#define DEBUG 0

static ssize_t _udp_recvfrom(int socket, void *_RESTRICT buffer, size_t length,
        int flags, struct sockaddr *_RESTRICT address,
        socklen_t *_RESTRICT address_len, nwio_udpopt_t *udpoptp);

ssize_t recvfrom(int socket, void *_RESTRICT buffer, size_t length,
        int flags, struct sockaddr *_RESTRICT address,
        socklen_t *_RESTRICT address_len)
{
        int r;
        nwio_udpopt_t udpopt;

        fprintf(stderr, "recvfrom: for fd %d\n", socket);

        r= ioctl(socket, NWIOGUDPOPT, &udpopt);
        if (r != -1 || (errno != ENOTTY && errno != EBADIOCTL))
        {
                if (r == -1)
                        return r;
                return _udp_recvfrom(socket, buffer, length, flags,
                        address, address_len, &udpopt);
        }

#if DEBUG
        fprintf(stderr, "recvfrom: not implemented for fd %d\n", socket);
#endif
        errno= ENOSYS;
        assert(0);
        return -1;
}

static ssize_t _udp_recvfrom(int socket, void *_RESTRICT buffer, size_t length,
        int flags, struct sockaddr *_RESTRICT address,
        socklen_t *_RESTRICT address_len, nwio_udpopt_t *udpoptp)
{
        int r, t_errno;
        size_t buflen, len;
        void *buf;
        struct sockaddr_in *sinp;
        udp_io_hdr_t *io_hdrp;
        struct sockaddr_in sin;

        if (flags)
        {
#if DEBUG
                fprintf(stderr, "recvfrom(udp): flags not implemented\n");
#endif
                errno= ENOSYS;
                return -1;
        }

        if (udpoptp->nwuo_flags & NWUO_RWDATONLY)
        {
#if DEBUG
                fprintf(stderr,
                        "recvfrom(udp): NWUO_RWDATONLY not implemented\n");
#endif
                errno= ENOSYS;
                return -1;
        }

        buflen= sizeof(*io_hdrp) + length;
        if (buflen < length)
        {       
                /* Overflow */
                errno= EMSGSIZE;
                return -1;
        }
        buf= malloc(buflen);
        if (buf == NULL)
                return -1;

        r= read(socket, buf, buflen);
        if (r == -1)
        {
                t_errno= errno;
#if DEBUG
                fprintf(stderr, "recvfrom(udp): read failed: %s\n",
                        strerror(errno));
                fprintf(stderr, "udp opt flags = 0x%x\n", udpoptp->nwuo_flags);
#endif
                free(buf);
                errno= t_errno;
                return -1;
        }

        assert(r >= sizeof(*io_hdrp));
        length= r-sizeof(*io_hdrp);

        io_hdrp= buf;
        memcpy(buffer, &io_hdrp[1], length);

        if (address != NULL)
        {
                sin.sin_family= AF_INET;
                sin.sin_addr.s_addr= io_hdrp->uih_src_addr;
                sin.sin_port= io_hdrp->uih_src_port;
                len= *address_len;
                if (len > sizeof(sin))
                        len= sizeof(sin);
                memcpy(address, &sin, len);
                *address_len= sizeof(sin);
        }       
        free(buf);
        return length;
}