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/*
* wip, a small TCP/IP stack.
* Copyright (C) 2025 Xavier Del Campo Romero
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
#include <wip/wip.h>
#include <wip/prv/io.h>
#include <wip/prv/log.h>
#include <wip/prv/icmp.h>
#include <wip/prv/icmp/types.h>
#include <stddef.h>
#include <string.h>
enum
{
TYPE,
CHECKSUM = 2,
ID = 4,
SEQ_NUM = 6,
DATA = 8
};
#if 0
static int get_type(struct wip_icmp *const icmp,
const unsigned char *const p, const size_t n)
{
unsigned char type;
if (icmp->read)
return 0;
type = p[0];
if (type != ECHO_REQUEST)
return -1;
wip_log("%s: got echo request\n");
icmp->type = type;
return 0;
}
static void get_checksum(struct wip_icmp *const icmp,
const unsigned char *const p, const size_t n)
{
size_t off;
struct wip_be16 v;
enum {END = CHECKSUM + sizeof v};
if (icmp->read >= END || n < END - icmp->read)
return;
off = CHECKSUM - icmp->read;
v.v[0] = p[off];
v.v[1] = p[off + 1];
icmp->exp_checksum = wip_be16(&v);
}
static void get_id(struct wip_icmp *const icmp, const unsigned char *const p,
const size_t n)
{
size_t off;
struct wip_be16 v;
enum {END = ID + sizeof v};
if (icmp->read >= END || n < END - icmp->read)
return;
off = ID - icmp->read;
v.v[0] = p[off];
v.v[1] = p[off + 1];
icmp->id = wip_be16(&v);
}
static void get_seqnum(struct wip_icmp *const icmp, const unsigned char *const p,
const size_t n)
{
size_t off;
struct wip_be16 v;
enum {END = SEQ_NUM + sizeof v};
if (icmp->read >= END || n < END - icmp->read)
return;
off = SEQ_NUM - icmp->read;
v.v[0] = p[off];
v.v[1] = p[off + 1];
icmp->seqnum = wip_be16(&v);
wip_log("chksum=%#x, id=%#x, seq_num=%#x\n", icmp->exp_checksum,
icmp->id, icmp->seqnum);
}
static enum wip_state get_data(struct wip *const w,
struct wip_icmp *const icmp, const unsigned char *const p, const size_t n)
{
const struct wip_cfg *const cfg = &w->cfg;
const size_t offset = icmp->read + n;
const void *src = p;
size_t sz = n;
if (offset < DATA)
return WIP_OK;
else if (!icmp->buf)
{
sz = n - DATA - icmp->read;
src = p + DATA - icmp->read;
if (!(icmp->buf = cfg->alloc(sz, cfg->user)))
return WIP_FATAL;
}
else
{
const size_t nsz = icmp->n + n;
enum {MAXSZ = 40};
void *buf;
if (nsz > MAXSZ)
return WIP_INVALID;
else if (!(buf = cfg->realloc(icmp->buf, nsz, cfg->user)))
return WIP_FATAL;
icmp->buf = buf;
}
memcpy((char *)icmp->buf + icmp->read, src, sz);
icmp->n += sz;
wip_log("data (%lu bytes): {", (unsigned long)icmp->n);
{
size_t i;
for (i = 0; i < icmp->n; i++)
{
wip_log("%#hhx", *((const char *)icmp->buf + i));
if (i + 1 < icmp->n)
wip_log(", ");
}
}
wip_log("}\n");
return WIP_OK;
}
#endif
enum wip_state wip_icmp_rx(struct wip *const w, const void *buf,
size_t n, void *const args)
{
struct wip_icmp *const icmp = args;
enum wip_state ret;
size_t r;
while ((ret = icmp->next(w, buf, n, icmp, &r)) == WIP_AGAIN)
{
buf = (const char *)buf + r;
n -= r;
}
return ret;
#if 0
enum wip_state (*next)(struct wip *, const void *, size_t,
struct wip_icmp *)
const struct wip_rx_sm_h *const h = &w->rx.sm.h;
const unsigned char *const p = buf;
const unsigned short dlen = wip_be16(&h->len) - h->header_sz;
enum wip_state ret;
size_t i;
if (get_type(icmp, buf, n))
return 0;
get_checksum(icmp, buf, n);
get_id(icmp, buf, n);
get_seqnum(icmp, buf, n);
if ((ret = get_data(w, icmp, buf, n)))
return ret;
for (i = 0; i < n; i++)
/* Avoid suming checksum */
if (icmp->read >= CHECKSUM || ((i != 2) && (i != 3)))
icmp->checksum += p[i];
if (icmp->read += n >= dlen)
{
wip_log("expected checksum=%#x, got=%#x\n",
icmp->exp_checksum, icmp->checksum);
}
return WIP_OK;
#endif
}
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