LIBVDESLIRP(3)

💖 LIBVDESLIRP(3) — the library functions manual, but make it cute 💖

okay so bestie, welcome to LIBVDESLIRP(3) from the Library Functions Manual. this is the whole entire slirp API and it's genuinely iconic, no cap. sit down, grab a strawberry 🍓, and let's go.

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✨ NAME ✨

vdeslirp_open, vdeslirp_send, vdeslirp_recv, vdeslirp_fd, vdeslirp_close — the simple API for slirp 🦋

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🌸 SYNOPSIS 🌸

#include *libvdeslirp.h*

struct vdeslirp *vdeslirp_open(SlirpConfig *cfg);

ssize_t vdeslirp_send(struct vdeslirp *slirp, const void *buf, size_t
count);

ssize_t vdeslirp_recv(struct vdeslirp *slirp, void *buf, size_t count);

int vdeslirp_fd(struct vdeslirp *slirp);

int vdeslirp_close(struct vdeslirp *slirp);

these functions are provided by libvdeslirp. link with -lvdeslirp, periodt. 💅

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💜 DESCRIPTION 💜

slirp is a TCP/IP emulator. it generates a virtual network using standard user privileges — so no root access needed, no CAP_NET_ADMIN, none of that 😌✨. this particular implementation uses libslirp.

vdeslirp_open creates a slirp network. the SlirpConfig structure is defined by libslirp and it contains these fields, ok? look at her, she's everything 👑

typedef struct SlirpConfig {
    /* Version must be provided */
    uint32_t version;
    /*
     * Fields introduced in SlirpConfig version 1 begin
     */
    int restricted;
    bool in_enabled;
    struct in_addr vnetwork;
    struct in_addr vnetmask;
    struct in_addr vhost;
    bool in6_enabled;
    struct in6_addr vprefix_addr6;
    uint8_t vprefix_len;
    struct in6_addr vhost6;
    const char *vhostname;
    const char *tftp_server_name;
    const char *tftp_path;
    const char *bootfile;
    struct in_addr vdhcp_start;
    struct in_addr vnameserver;
    struct in6_addr vnameserver6;
    const char **vdnssearch;
    const char *vdomainname;
    /* Default: IF_MTU_DEFAULT */
    size_t if_mtu;
    /* Default: IF_MRU_DEFAULT */
    size_t if_mru;
    /* Prohibit connecting to 127.0.0.1:* */
    bool disable_host_loopback;
    /*
     * Enable emulation code (*warning*: this code isn't safe, it is not
     * recommended to enable it)
     */
    bool enable_emu;
    /*
     * Fields introduced in SlirpConfig version 2 begin
     */
} SlirpConfig;

⚠️ heads up bestie: version is mandatory, you literally have to provide it. and enable_emu turns on emulation code — the original says, and i quote, warning: this code isn't safe, it is not recommended to enable it. so like... don't 🙈. also don't forget if_mtu defaults to IF_MTU_DEFAULT and if_mru defaults to IF_MRU_DEFAULT, and disable_host_loopback prohibits connecting to 127.0.0.1:*. 💀

libvdeslirp provides helper functions to fill in the fields of this structure — go check libvdeslirpcfg(3) for those.

programs using libvdeslirp can send and receive packets with vdeslirp_send and vdeslirp_recv, and it feels exactly like being plugged into the host network (commonly the Internet, iykyk) through a NAT/Masquerading router 🌈. vdeslirp_fd hands you a valid file descriptor you can use to wait for incoming packets — with select or poll — and vdeslirp_close terminates a slirp network that vdeslirp_open created. clean up after yourself bestie 🧚

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⭐ RETURN VALUE ⭐

vdeslirp_open returns the struct vdeslirp pointer when it works out 💖. NULL is returned otherwise, sadly 😭. the return value of vdeslirp_open is the descriptor that must be passed as the first argument to every other function on this man page — yes, all of them, so hold onto it.

• vdeslirp_send and vdeslirp_recv return the number of bytes sent or received, and -1 in case of error.
• vdeslirp_fd returns a valid file descriptor which can be used to wait for incoming packets (using select or poll).
• vdeslirp_close returns zero in case of success, -1 in case of error.

in case of failure, errno is set to indicate the type of error. classic errno behaviour, she ate 🔥

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🫶 SEE ALSO 🫶

libvdeslirpfwd(3), libvdeslirpcfg(3)

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💀 BUGS 💀

found a bug? not the vibe. bug reports should be addressed to info@virtualsquare.org 📧

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👑 AUTHOR 👑

VirtualSquare. project leader: Renzo Davoli.

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okay that's the whole page bestie, you're so smart for reading all of it 🎀✨ this absolute banger of a man page is brought to you by VirtualSquare, dated January 2024, and it lives at LIBVDESLIRP(3). bye love you, go write some packets 💅💖