diff options
Diffstat (limited to 'src/protocol/icmp/rx.c')
| -rw-r--r-- | src/protocol/icmp/rx.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/protocol/icmp/rx.c b/src/protocol/icmp/rx.c new file mode 100644 index 0000000..8e543f9 --- /dev/null +++ b/src/protocol/icmp/rx.c @@ -0,0 +1,200 @@ +/* + * 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 +} |