git: 6775ef4188b4 - main - netinet6: Implement in6_cksum_partial() using m_apply()
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Date: Fri, 23 Jun 2023 15:09:55 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=6775ef4188b4d4c023e76ebd2b71fa8c2c7e7cd2
commit 6775ef4188b4d4c023e76ebd2b71fa8c2c7e7cd2
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2023-06-23 13:55:43 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2023-06-23 13:55:43 +0000
netinet6: Implement in6_cksum_partial() using m_apply()
This ensures that in6_cksum_partial() can be applied to unmapped mbufs,
which can happen at least when icmp6_reflect() quotes a packet.
The basic idea is to restructure in6_cksum_partial() to operate on one
mbuf at a time. If the buffer length is odd or unaligned, an extra
residual byte may be returned, to be incorporated into the checksum when
processing the next buffer.
PR: 268400
Reviewed by: cy
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D40598
---
sys/netinet6/in6.h | 6 +-
sys/netinet6/in6_cksum.c | 300 +++++++++++++++++++++--------------------------
2 files changed, 139 insertions(+), 167 deletions(-)
diff --git a/sys/netinet6/in6.h b/sys/netinet6/in6.h
index 41fe07fe093d..c15b2485964a 100644
--- a/sys/netinet6/in6.h
+++ b/sys/netinet6/in6.h
@@ -659,10 +659,10 @@ struct ip6_mtuinfo {
struct cmsghdr;
struct ip6_hdr;
+int in6_cksum(struct mbuf *, uint8_t, uint32_t, uint32_t);
+int in6_cksum_partial(struct mbuf *, uint8_t, uint32_t, uint32_t, uint32_t);
int in6_cksum_pseudo(struct ip6_hdr *, uint32_t, uint8_t, uint16_t);
-int in6_cksum(struct mbuf *, u_int8_t, u_int32_t, u_int32_t);
-int in6_cksum_partial(struct mbuf *, u_int8_t, u_int32_t, u_int32_t,
- u_int32_t);
+
int in6_localaddr(struct in6_addr *);
int in6_localip(struct in6_addr *);
bool in6_localip_fib(struct in6_addr *, uint16_t);
diff --git a/sys/netinet6/in6_cksum.c b/sys/netinet6/in6_cksum.c
index c4624b90b6a1..a93db45eb968 100644
--- a/sys/netinet6/in6_cksum.c
+++ b/sys/netinet6/in6_cksum.c
@@ -82,6 +82,16 @@ __FBSDID("$FreeBSD$");
#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
+union l_util {
+ uint16_t s[2];
+ uint32_t l;
+};
+
+union s_util {
+ uint8_t c[2];
+ uint16_t s;
+};
+
static int
_in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
{
@@ -131,17 +141,115 @@ _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
int
in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
{
+ union l_util l_util;
int sum;
- union {
- u_int16_t s[2];
- u_int32_t l;
- } l_util;
sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
REDUCE;
return (sum);
}
+static int
+in6_cksumdata(void *data, int *lenp, uint8_t *residp, int rlen)
+{
+ union l_util l_util;
+ union s_util s_util;
+ uint16_t *w;
+ int len, sum;
+ bool byte_swapped;
+
+ KASSERT(*lenp >= 0, ("%s: negative len %d", __func__, *lenp));
+ KASSERT(rlen == 0 || rlen == 1, ("%s: rlen %d", __func__, rlen));
+
+ len = *lenp;
+ sum = 0;
+
+ if (len == 0) {
+ len = rlen;
+ goto out;
+ }
+
+ byte_swapped = false;
+ w = data;
+
+ /*
+ * Do we have a residual byte left over from the previous buffer?
+ */
+ if (rlen == 1) {
+ s_util.c[0] = *residp;
+ s_util.c[1] = *(uint8_t *)w;
+ sum += s_util.s;
+ w = (uint16_t *)((uint8_t *)w + 1);
+ len--;
+ rlen = 0;
+ }
+
+ /*
+ * Force to even boundary.
+ */
+ if ((1 & (uintptr_t)w) && len > 0) {
+ REDUCE;
+ sum <<= 8;
+ s_util.c[0] = *(uint8_t *)w;
+ w = (uint16_t *)((uint8_t *)w + 1);
+ len--;
+ byte_swapped = true;
+ }
+
+ /*
+ * Unroll the loop to make overhead from branches &c small.
+ */
+ while ((len -= 32) >= 0) {
+ sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+ sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
+ sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
+ sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
+ w += 16;
+ }
+ len += 32;
+ while ((len -= 8) >= 0) {
+ sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
+ w += 4;
+ }
+ len += 8;
+ if (len == 0 && !byte_swapped)
+ goto out;
+ REDUCE;
+ while ((len -= 2) >= 0) {
+ sum += *w++;
+ }
+ if (byte_swapped) {
+ REDUCE;
+ sum <<= 8;
+ if (len == -1) {
+ s_util.c[1] = *(uint8_t *)w;
+ sum += s_util.s;
+ } else /* len == -2 */
+ *residp = s_util.c[0];
+ len++;
+ } else if (len == -1)
+ *residp = *(uint8_t *)w;
+out:
+ *lenp = len & 1;
+ return (sum);
+}
+
+struct in6_cksum_partial_arg {
+ int sum;
+ int rlen;
+ uint8_t resid;
+};
+
+static int
+in6_cksum_partial_one(void *_arg, void *data, u_int len)
+{
+ struct in6_cksum_partial_arg *arg = _arg;
+
+ arg->sum += in6_cksumdata(data, &len, &arg->resid, arg->rlen);
+ arg->rlen = len;
+ return (0);
+}
+
/*
* m MUST contain a contiguous IP6 header.
* off is an offset where TCP/UDP/ICMP6 header starts.
@@ -150,33 +258,29 @@ in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
* cov is the number of bytes to be taken into account for the checksum
*/
int
-in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
- u_int32_t len, u_int32_t cov)
+in6_cksum_partial(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len,
+ uint32_t cov)
{
+ struct in6_cksum_partial_arg arg;
+ union l_util l_util;
+ union s_util s_util;
struct ip6_hdr *ip6;
- u_int16_t *w, scope;
- int byte_swapped, mlen;
+ uint16_t *w, scope;
int sum;
union {
- u_int16_t phs[4];
+ uint16_t phs[4];
struct {
- u_int32_t ph_len;
- u_int8_t ph_zero[3];
- u_int8_t ph_nxt;
+ uint32_t ph_len;
+ uint8_t ph_zero[3];
+ uint8_t ph_nxt;
} __packed ph;
} uph;
- union {
- u_int8_t c[2];
- u_int16_t s;
- } s_util;
- union {
- u_int16_t s[2];
- u_int32_t l;
- } l_util;
/* Sanity check. */
KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
"len(%d)", __func__, m->m_pkthdr.len, off, len));
+ KASSERT(m->m_len >= sizeof(*ip6),
+ ("%s: mbuf len %d < sizeof(ip6)", __func__, m->m_len));
/*
* First create IP6 pseudo header and calculate a summary.
@@ -193,7 +297,7 @@ in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
/* IPv6 source address. */
scope = in6_getscope(&ip6->ip6_src);
- w = (u_int16_t *)&ip6->ip6_src;
+ w = (uint16_t *)&ip6->ip6_src;
sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
if (scope != 0)
@@ -201,158 +305,26 @@ in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
/* IPv6 destination address. */
scope = in6_getscope(&ip6->ip6_dst);
- w = (u_int16_t *)&ip6->ip6_dst;
+ w = (uint16_t *)&ip6->ip6_dst;
sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
if (scope != 0)
sum -= scope;
/*
- * Secondly calculate a summary of the first mbuf excluding offset.
+ * Loop over the rest of the mbuf chain and compute the rest of the
+ * checksum. m_apply() handles unmapped mbufs.
*/
- while (off > 0) {
- if (m->m_len <= off)
- off -= m->m_len;
- else
- break;
- m = m->m_next;
- }
- w = (u_int16_t *)(mtod(m, u_char *) + off);
- mlen = m->m_len - off;
- if (cov < mlen)
- mlen = cov;
- cov -= mlen;
- /*
- * Force to even boundary.
- */
- if ((1 & (long)w) && (mlen > 0)) {
- REDUCE;
- sum <<= 8;
- s_util.c[0] = *(u_char *)w;
- w = (u_int16_t *)((char *)w + 1);
- mlen--;
- byte_swapped = 1;
- } else
- byte_swapped = 0;
+ arg.sum = sum;
+ arg.rlen = 0;
+ (void)m_apply(m, off, cov, in6_cksum_partial_one, &arg);
+ sum = arg.sum;
/*
- * Unroll the loop to make overhead from
- * branches &c small.
+ * Handle a residual byte.
*/
- while ((mlen -= 32) >= 0) {
- sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
- sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
- sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
- sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
- w += 16;
- }
- mlen += 32;
- while ((mlen -= 8) >= 0) {
- sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
- w += 4;
- }
- mlen += 8;
- if (mlen == 0 && byte_swapped == 0)
- goto next;
- REDUCE;
- while ((mlen -= 2) >= 0) {
- sum += *w++;
- }
- if (byte_swapped) {
- REDUCE;
- sum <<= 8;
- byte_swapped = 0;
- if (mlen == -1) {
- s_util.c[1] = *(char *)w;
- sum += s_util.s;
- mlen = 0;
- } else
- mlen = -1;
- } else if (mlen == -1)
- s_util.c[0] = *(char *)w;
- next:
- m = m->m_next;
-
- /*
- * Lastly calculate a summary of the rest of mbufs.
- */
-
- for (;m && cov; m = m->m_next) {
- if (m->m_len == 0)
- continue;
- w = mtod(m, u_int16_t *);
- if (mlen == -1) {
- /*
- * The first byte of this mbuf is the continuation
- * of a word spanning between this mbuf and the
- * last mbuf.
- *
- * s_util.c[0] is already saved when scanning previous
- * mbuf.
- */
- s_util.c[1] = *(char *)w;
- sum += s_util.s;
- w = (u_int16_t *)((char *)w + 1);
- mlen = m->m_len - 1;
- cov--;
- } else
- mlen = m->m_len;
- if (cov < mlen)
- mlen = cov;
- cov -= mlen;
- /*
- * Force to even boundary.
- */
- if ((1 & (long) w) && (mlen > 0)) {
- REDUCE;
- sum <<= 8;
- s_util.c[0] = *(u_char *)w;
- w = (u_int16_t *)((char *)w + 1);
- mlen--;
- byte_swapped = 1;
- }
- /*
- * Unroll the loop to make overhead from
- * branches &c small.
- */
- while ((mlen -= 32) >= 0) {
- sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
- sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
- sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
- sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
- w += 16;
- }
- mlen += 32;
- while ((mlen -= 8) >= 0) {
- sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
- w += 4;
- }
- mlen += 8;
- if (mlen == 0 && byte_swapped == 0)
- continue;
- REDUCE;
- while ((mlen -= 2) >= 0) {
- sum += *w++;
- }
- if (byte_swapped) {
- REDUCE;
- sum <<= 8;
- byte_swapped = 0;
- if (mlen == -1) {
- s_util.c[1] = *(char *)w;
- sum += s_util.s;
- mlen = 0;
- } else
- mlen = -1;
- } else if (mlen == -1)
- s_util.c[0] = *(char *)w;
- }
- if (cov)
- panic("in6_cksum: out of data");
- if (mlen == -1) {
- /* The last mbuf has odd # of bytes. Follow the
- standard (the odd byte may be shifted left by 8 bits
- or not as determined by endian-ness of the machine) */
+ if (arg.rlen == 1) {
+ s_util.c[0] = arg.resid;
s_util.c[1] = 0;
sum += s_util.s;
}
@@ -361,7 +333,7 @@ in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
}
int
-in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
+in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len)
{
return (in6_cksum_partial(m, nxt, off, len, len));
}