diff options
| -rw-r--r-- | iov.c | 42 | ||||
| -rw-r--r-- | iov.h | 2 | ||||
| -rw-r--r-- | tap.c | 12 |
3 files changed, 40 insertions, 16 deletions
@@ -25,6 +25,36 @@ #include "util.h" #include "iov.h" + +/* iov_skip_bytes() - Skip the first n bytes into an IO vector + * @iov: IO vector + * @n: Number of entries in @iov + * @vec_offset: Total byte offset into the IO vector + * @buf_offset: Offset into a single buffer of the IO vector + * + * Return: index I of individual struct iovec which contains the byte at + * @vec_offset bytes into the vector (as though all its buffers were + * contiguous). If @buf_offset is non-NULL, update it to the offset of + * that byte within @iov[I] (guaranteed to be less than @iov[I].iov_len) + * If the whole vector has <= @vec_offset bytes, return @n. + */ +size_t iov_skip_bytes(const struct iovec *iov, size_t n, + size_t vec_offset, size_t *buf_offset) +{ + size_t offset = vec_offset, i; + + for (i = 0; i < n; i++) { + if (offset < iov[i].iov_len) + break; + offset -= iov[i].iov_len; + } + + if (buf_offset) + *buf_offset = offset; + + return i; +} + /** * iov_from_buf - Copy data from a buffer to an I/O vector (struct iovec) * efficiently. @@ -51,9 +81,7 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt, return bytes; } - /* skipping offset bytes in the iovec */ - for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++) - offset -= iov[i].iov_len; + i = iov_skip_bytes(iov, iov_cnt, offset, &offset); /* copying data */ for (copied = 0; copied < bytes && i < iov_cnt; i++) { @@ -94,9 +122,7 @@ size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt, return bytes; } - /* skipping offset bytes in the iovec */ - for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++) - offset -= iov[i].iov_len; + i = iov_skip_bytes(iov, iov_cnt, offset, &offset); /* copying data */ for (copied = 0; copied < bytes && i < iov_cnt; i++) { @@ -155,9 +181,7 @@ unsigned iov_copy(struct iovec *dst_iov, size_t dst_iov_cnt, { unsigned int i, j; - /* skipping offset bytes in the iovec */ - for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++) - offset -= iov[i].iov_len; + i = iov_skip_bytes(iov, iov_cnt, offset, &offset); /* copying data */ for (j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) { @@ -18,6 +18,8 @@ #include <unistd.h> #include <string.h> +size_t iov_skip_bytes(const struct iovec *iov, size_t n, + size_t vec_offset, size_t *buf_offset); size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt, size_t offset, const void *buf, size_t bytes); size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt, @@ -45,6 +45,7 @@ #include "checksum.h" #include "util.h" +#include "iov.h" #include "passt.h" #include "arp.h" #include "dhcp.h" @@ -389,6 +390,7 @@ static size_t tap_send_frames_passt(const struct ctx *c, .msg_iov = (void *)iov, .msg_iovlen = n, }; + size_t buf_offset; unsigned int i; ssize_t sent; @@ -397,15 +399,11 @@ static size_t tap_send_frames_passt(const struct ctx *c, return 0; /* Check for any partial frames due to short send */ - for (i = 0; i < n; i++) { - if ((size_t)sent < iov[i].iov_len) - break; - sent -= iov[i].iov_len; - } + i = iov_skip_bytes(iov, n, sent, &buf_offset); - if (i < n && sent) { + if (i < n && buf_offset) { /* A partial frame was sent */ - tap_send_remainder(c, &iov[i], sent); + tap_send_remainder(c, &iov[i], buf_offset); i++; } |