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// Copyright (c) 2022 Johannes Stoelp
#include "dhcp.h"
#include "utils.h"
std::optional<struct option_view> get_option(const u8* opt, usize len, dhcp_option search_tag) {
const u8* end = opt + len;
while (opt < end) {
// Get tag of current option.
dhcp_option tag = from_raw<dhcp_option>(*opt++);
if (tag == dhcp_option::END) {
break;
}
// Extract length of current option.
usize len = *opt++;
if (tag == search_tag) {
if (static_cast<usize>(end - opt) < len) {
// If length is malformed.
return std::nullopt;
} else {
// Option found.
return {{opt, len}};
}
}
// Advance option iterator to beginning of next option.
opt = opt + len;
}
// Option not found.
return std::nullopt;
}
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